CBSE Class 10 Science Our Environment Worksheet

Read and download free pdf of CBSE Class 10 Science Our Environment Worksheet. Students and teachers of Class 10 Science can get free printable Worksheets for Class 10 Science Chapter 15 Our Environment in PDF format prepared as per the latest syllabus and examination pattern in your schools. Class 10 students should practice questions and answers given here for Science in Class 10 which will help them to improve your knowledge of all important chapters and its topics. Students should also download free pdf of Class 10 Science Worksheets prepared by school teachers as per the latest NCERT, CBSE, KVS books and syllabus issued this academic year and solve important problems with solutions on daily basis to get more score in school exams and tests

Worksheet for Class 10 Science Chapter 15 Our Environment

Class 10 Science students should refer to the following printable worksheet in Pdf for Chapter 15 Our Environment in Class 10. This test paper with questions and answers for Class 10 will be very useful for exams and help you to score good marks

Class 10 Science Worksheet for Chapter 15 Our Environment

Question. In the biosphere, which of the following is the ultimate source of energy?
(a) Carbon
(b) Water
(c) Sunlight
(d) Nitrogen

Answer : C

Question. The diagram shows part of a river into which sewage is being pumped. Some of the effects of adding sewage to the river are shown in the graph. At which point in the river are decomposers most active?

CBSE Class 10 Science Our Environment Worksheet_1

(a) D
(b) C
(c) B
(d) A

Answer : C

Question. Sulphur dioxide affects
(a) haemoglobin of blood
(b) Arteries
(c) Alveoli of lungs
(d) Nerves

Answer : C

Question. CO2 absorbs some of the ......... that radiates from the surface of earth to space
(a) ozone
(b) heat
(c) food web
(d) producer

Answer : B

Question. An example of a producer in the aquatic food web would be
(a) Duckweed
(b) Ducks
(c) Fish
(d) Insects

Answer : A

Question. The diagram shows the flow of energy through an ecosystem.

CBSE Class 10 Science Our Environment Worksheet_2

Answer : C

Question. Sun gives radiations in the form of
(a) Infra-red radiation
(b) Arteries
(c) Alveoli of lungs
(d) Nerves

Answer : D

Question. Why do scientists think that human-induced global warming will be more harmful to plants and animals than were past, natural climate fluctuations?
(a) because temperatures will change faster
(b) because the temperature changes will be larger
(c) because species now are less adaptable than species in the past
(d) because ecosystems are now more complicated than they used to be

Answer : A

Question. For corrosion of metals, there should be
(a) Exposed surface of metal
(b) Moisture
(c) Air
(d) All of the above

Answer : D

Question. As energy is passed from one trophic level to another, the amount of usable energy
(a) increases
(b) decreases
(c) remains the same
(d) energy is not passed from one trophic level to another

Answer : B

Question. The following graph shows the concentration of oxygen in a river, measured at stations 1-5 each 100 m apart. A sewage outflow is observed just after station
1. At which stations will the concentration of organic matter be lowest?

CBSE Class 10 Science Our Environment Worksheet_3

(a) 1 and 5
(b) 2 and 3
(c) 3 and 4
(d) 4 and 5

Answer : A

Question. The biological process by which carbon is returned to its reservoir is
(a) photosynthesis
(b) de-nitrification
(c) carbon fixation
(d) cellular respiration

Answer : D

Question. Which of the following is not a functional component of an ecosystem?
(a) Communities
(b) Decomposers
(c) Sunlight
(d) Energy flow

Answer : D

Question. In a food chain, the snake predated as rabbit which fed on fresh green bushes. What percentage amount of the energy accumulated by rabbit, would be acquired by snakes?
(a) 90%
(b) 10%
(c) 50%
(d) 25%

Answer : B

Question. The last chain of food is
(a) producers
(b) decomposers
(c) parasites
(d) none of the above

Answer : B

Question. The diagram represents the flow of substances within a balanced ecosystem. The boxes are various trophic levels. Which box represents the producers?

CBSE Class 10 Science Our Environment Worksheet_4

 

(a) B
(b) D
(c) A
(d) C

Answer : B

Question. Burning to waste products at high temperature to form ash, reduces waste considerably. This method of waste disposal is called
(a) composting
(b) sewage treatment
(c) recycling
(d) incineration

Answer : D

Question. In an ecosystem green plants are known as
(a) primary consumers
(b) secondary consumers
(c) producers
(d) tertiary consumers

Answer : C

Question. Replacing of plastic cups by the paper cups for selling tea on train is preferred because
(a) paper cups are more aesthetic
(b) paper cups are more hygienic
(c) paper cups are cheaper
(d) paper cups are biodegradable and eco-friendly

Answer : D

Question. The diagram shows the organisms in a habitat.

CBSE Class 10 Science Our Environment Worksheet_5

Which of the following indicates the feeding relationships of these organisms?

CBSE Class 10 Science Our Environment Worksheet_6

Answer : C

Question. Free services provided to humans by ecosystems include
(a) control of atmospheric carbon dioxide concentration
(b) prevention of soil erosion
(c) filtering of pollutants from water and air
(d) all of the above

Answer : D

Question. Trophic levels are formed by-
(a) only plants
(b) only animals
(c) only carnivores
(d) organisms linked in food chain

Answer : D

Question. Fertilisers are used on farmlands to increase the nutritive quality of soil and thus, the crop productivity.
However, they greatly impact our environment in negative ways. A fertiliser industry is planning to release nitrate-free or reduced nitrate containing fertiliser to make it more environment-freindly. This control of nitrate rich fertilisers is necessary because
(a) nitrates cause acid rain, killing trees and fishes when released in the environment
(b) they decrease the natural fertility to the soil 
(c) nitrates may lead to excessive growth of water plants
(d) it poisons different crop plants

Answer : C

Question. Food web is the
(a) food that a spider collects using its web
(b) network of interlinked trophic levels
(c) network of interlinked food chains
(d) display of food items on a website

Answer : C

Question. Each step in a food chain is called a
(a) trophic level
(b) consumer level
(c) food web
(d) producer

Answer : A

Question. The part of earth comprising water is called an
(a) atmoshphere
(b) hydrosphere
(c) lithosphere
(d) none of the above

Answer : B

Question. Individuals of any species at a place form
(a) biotic community
(b) ecosystem
(c) population
(d) biome

Answer : C

Question. As a black widow spider consumes her mate, what is the lowest trophic level she could be occupying
(a) third
(b) first
(c) second
(d) fourth

Answer : D

Question. Human-caused changes to the nitrogen cycle are expected to result in
(a) an increase in acid rain
(b) an increase in the loss of species from ecosystems
(c) higher concentrations of a greenhouse gas
(d) all of the above

Answer : D

Question. A decrease in the grass population will most immediately decrease the available energy for the
(a) mouse
(b) snake
(c) hawk
(d) frog

Answer : A

Question. As a biologist, if you become very interested in the study of the interaction of organisms with each other and the environment your subspeciality would be
(a) Zoology
(b) Ecology
(c) Botany
(d) Herpetology

Answer : B

Question. The number of trophic levels in a food chain are: 
a. Two to three
b. Three to four
c. Four to five
d. Unlimited
 
Answer : B
Explanation: There is a loss of energy as the energy is transferred from a lower trophic level to a higher trophic level; this limits the number of trophic levels in a food-chain. The food chains generally consist of only three or four steps since very little usable energy remains after four trophic levels.
 
Question.  “Nitrous oxide is a green house gas”. The above statement is: 
a. True
b. Partially false
c. False
d. Partially true
 
Answer : A 
Explanation: Nitrous oxide occurs in small amounts in the atmosphere, but has been found to be a major scavenger of stratospheric ozone, with an impact comparable to that of the CFCs. According to an estimation, 30% of the N2O in the atmosphere is the result of human activity, chiefly agriculture. It also has a significant global warming potential as a greenhouse gas.
 
Question.  Montreal protocol became effective in:
a. 1985
b. 1987
c. 1992
d. 1989
 
Answer : D 
Explanation: The Montreal Protocol became effective in 1989. The Montreal Protocol is a protocol to the Vienna Convention for the Protection of the Ozone Layer. It is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are
responsible for ozone depletion.
 
Question. According to 10% law, the energy available to each successive level is _________ of the previous level. 
a. 100%
b. 10%
c. None
d. 1%
 
Answer : B
Explanation: According to 10% law, the energy available to each successive trophic level is 10% of the previous trophic level. An average of 10% of the food eaten by a consumer is turned into its own body and made available for the next level of consumers. 10% can be taken as the average value for the amount of organic matter that is present at each step and reaches the next level of consumers.
 
Question.  Which of the following limits the number of trophic levels in a food chain? 
a. Decrease in energy at higher trophic levels
b. Polluted air
c. Deficient food supply
d. Water
 
Answer : A 
Explanation: There is a loss of energy as the energy is transferred from a lower trophic level to a higher trophic level; this limits the number of trophic levels in a food-chain. The food chains generally consist of only three or four steps since very little usable energy remains after four trophic levels.
 

Fill In The Blank

Question. The waste we generate may be .......... or .........
Answer : Biodegradable, non-biodegradable.

Question. The disposal of the waste we generate is causing serious ......... problems.
Answer : Environmental

Question. The decomposers comprising micro-organisms like .......... and .........
Answer : Bacteria, Fungi

Question. The materials which are locked up in dead complex organic substance are made available to plants in the form of simple inorganic substances by the ..........
Answer : Decomposers

Question. Substances that are broken-down by biological processes are said to be ..........
Answer : Biodegradable

Question. It is .......... to sleep in closed room with a coke fire burning.
Answer : Dangerous

Question. Substances that are not broken-down by biological processes are said to be ..........
Answer : Non-biodegradable

Question. Organisms can be grouped as producers, consumers and .......... according to the manner in which they obtain their substances from the environment.
Answer : Decomposers

Question. Every food chain starts from ......... .
Answer : Producers

Question. The energy flows from autotrophs to the heterotrophs and ......... .
Answer : Decomposers

Question. Burning of fossil fuels is the main cause of release of .......... gas in air.
Answer : Carbon dioxide

Question. The inter locking pattern of various food chains is referred as ......... .
Answer : Food Web

Question. The total amount of .......... per unit time produced in an ecosystem is called the gross primary productivity.
Answer : Organic material

Question. The use of chemicals like CFCs has endangere the .......... layer.
Answer : Ozone

Question. Total number of individuals of any species at a place is known as .........
Answer : Population

 

True/false

Question. Biodegradable wastes should be separated and kept in blue colour bins for garbage collectors.
Answer : False

Question. Specific enzymes are needed for the break-down of a particular substance.
Answer : True

Question. Secondary consumers in food chain are always carnivores.
Answer : True

Question. Earth is kept warm due to green house flux.
Answer : True

Question. Carbon dioxide causes depletion of ozone layer thereby allowing more UV-radiations to reach the earth.
Answer : False

Question. Forests, and ponds are natural ecosystem while gardens and fields are artifical ecosystem.
Answer : True

Question. Phytoplanktons are primary consumers.
Answer : False

Question. Ecology is the scientific study of the interaction of organisms with each other and the environment.
Answer : True

Question. UNEP has foraged an agreement to freeze CFC production.
Answer : True

Question. Non-biodegradable articles are the ones which cannot be digested.
Answer : True

Question. Organism can make organic compounds from inorganic substances by using the radiant energy of the sun in the presence of chlorophyll.
Answer : True

Question. Forests, and ponds are natural ecosystem while gardens and fields are artifical ecosystem.
Answer : True

Question. Different materials are not cycled in the environment.
Answer : False

Question. Wastes are of two types, biodegradable and nonbiodegradable.
Answer : True

Question. The abiotic components of the environment are the living factors.
Answer : False

Question. Ozone is formed in stratosphere by action of ultraviolet radiations on oxygen.
Answer : True

 

Assertion And Reason

DIRECTION : In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
(e) Both Assertion and Reason are false.

Question. Assertion : Aquariums are known as the man-made ecosystems.
Reason : Aquariums are created and maintained by humans.

Answer : A

Question. Assertion : First trophic level in a food chain is always a green plant.
Reason : Green plants are called producers.

Answer : A

Question. Assertion : Biomagnification is caused due to the accumulation of biodegradable toxicants in organisms at each successive trophic level.
Reason : Biomagnification leads to the maximum accumulation of chemicals in small fishes.

Answer : E

Question. Assertion : Man is a herbivore.
Reason : Omnivores eat both plant food and meat of animals.

Answer : D

Question. Assertion : Tropical rain forests are disappearing fast from developing countries such as India.
Reason : No value is attached to these forests because these are poor in biodiversity.

Answer : C

Question. Assertion : Animals adopt different strategies to survive in hostile environment.
Reason : Praying mantis is green in colour which merges with plant foliage.

Answer : A

Question. Assertion : A network of food chains existing together in an ecosystem is known as food web.
Reason : An animal like kite cannot be a part of a food web.

Answer : C

Question. Assertion : Abiotic component of an ecosystem involves cycling of material and flow of energy.
Reason : This is essential to keep biotic factors alive.

Answer : A

Question. Assertion : Supersonic jets cause pollution as they thin out ozone.
Reason : Depletion of ozone cause green house effect.

Answer : A

Question. Assertion : Flow of energy in a food chain is unidirectional.
Reason : Energy captured by autotrophs does not revert back to the solar input and it passes to the herbivores.

Answer : A


Very Short Answers :

Question. What percentage of solar energy is trapped and utilized by plants? 
Answer :  Plants trap only 1% of total sun’s energy, which is utilized by plants in the process of photosynthesis.
 
Question.  Which of the following belongs to the first trophic level? Grasshopper rose plant, cockroach, vulture, neem plant. 
Answer :  Rose plant and neem plant as both of them are producers and a food chain always start with producers which form the first trophic level.
 
Question.  Would you eat animals or plants to get more calories of heat? 
Answer :   We should eat plants to get more calories of heat.
 
Question. Write a food chain having two trophic levels. 
Answer :  Plants → Man
 
Question.  In an ecosystem, how the biotic and abiotic components are dependent on each other? 
Answer : All living organisms not only interact with each other but also with their environment.
Their growth, reproduction and other activities are affected by temperature, water, humidity, etc., which constitutes abiotic components. Even their body structure and needs depend upon the surroundings. Hence, biotic and abiotic components are dependent on each other. 

Question. Write the common food chain of a pond ecosystem.
Answer: Phytoplanktons → Zooplanktons → Fish → Bird

Question. What will be the amount of energy available to the organisms of the second trophic level of a food chain, if the energy available at the first trophic level is 10,000 J?
Answer: 1000 J amount of energy will be available to the organisms of the second trophic level of a food chain, if the energy available at the first trophic level is 10,000 J.

Question. What is the role of decomposers in the ecosystem? 
Answer: Decomposers act upon dead and decay organisms and convert them into simpler forms. These simple substances get mixed up in the soil and are used as nutrients by the producers. From producers it goes to consumers and so on. They maintain the balance in the ecosystem and provide space for new life in ecosystem.

Question. If a harmful chemical enters a food chain comprising snakes, hawks, mice and plants which of these organisms is likely to have maximum concentration of the harmful chemicals in its body ?
Answer: Hawks are likely to have maximum concentration of the harmful chemicals in their body as they are placed at top in this example of food chain.

Question. What are the by-products of fertilizer industries? How do they affect the environment?
Answer: The by-products of fertilizer industries are oxides of nitrogen and sulphur which when released into atmosphere causes air pollution. They are mainly responsible for formation of acid rain. Acid rain damages marbles of monuments, statues etc. Acid rain also reduces the fertility of soil by decreasing the pH of soil thus growth of food crops is affected. They affect the microbes in soil and aquatic organisms in water bodies.

Question. Why is forest considered a natural ecosystem?
Answer: Forests are considered as natural ecosystem because they have species of plants and animals that grow without human intervention and they are naturally sustainable.

Question. Why is improper disposal of waste a curse to environment ?
Answer: Improper disposal of waste would lead to environmental pollution, which causes harmful effects on living organisms like plants, animals, human beings etc.

Question. In the following food chain, grass provides 4000 J of energy to the grasshopper. Grass, grasshopper, frogs, snakes.
How much energy will be available to snakes and frogs?
Answer: If grass provides 4000 J energy, then according to 10 per cent law, it will give 10% of its energy to next trophic level.
Hence,
Grass ----> Grasshopper ------->
(4000 J) (400 J)
Frogs -------> Snakes (40 J) (4 J)
So, for snakes and frogs, 4 J and 40 J energy will be available by
10 per cent law

Question. What limits the number of trophic levels in a food chain?
Answer: The flow of energy in each trophic level follows 10% law i.e., only 10% of the energy is available to the next higher trophic level hence the amount of energy goes on decreasing at each trophic level which limits the number of trophic levels in a food chain.

Question. Why is biogas considered an excellent fuel?
Answer: Biogas is considered as an excellent fuel because:
(i) It causes no pollution, as it is environmental friendly.
(ii) Biogas plant from which biogas is produced serves as an excellent way of waste disposal.
(iii) It is economical and produces a large amount of heat per unit mass.

Question. Write the name of the main constituent of biogas. Also state its percentage.
Answer: Methane is the main constituent of biogas. Its formula is CH4. Its percentage is approximately 50-75%.

Question. In a food chain of frog, grass, insect and snake assign trophic level to frog.*
Answer: Frog will be at third trophic level.
Grass → Insect → Frog → Snake

Question. Consider a food chain of the following:
Fish, crab, plankton, shark.
Arrange the above chain in proper order of trophic level. Assign trophic level to shark.
Answer: Plankton → Crab → Fish → Shark.
Shark occupies fourth tropic level (Tertiary consumer).

Question. Select the mis-matched pair and correct it:
(a) Detritivores–Organisms which feed on detritus and degrade into simple substances.
(b) Ecosystem–Abiotic and biotic components of environment.
(c) Trophic level–It is made of interlinking of food chains
(d) Producers–They synthesize their own food from inorganic substances
Answer: (c) Trophic levels are distinct sequential steps in the food chain where transfer of energy occurs.

Question. Name two natural ecosystems.
Answer: River, pond, forest, ocean etc., are natural ecosystems.

Question. What will happen if we kill all the organisms in one trophic level?
Answer: If we kill all the organisms of one trophic level, it will lead to an increase in the number of organisms at the lower trophic level and decrease in the number of organisms at the higher trophic level. This will result in disruption in the food web and hence the ecosystem.

Question. Expand the term UNEP.
Answer: United Nations Environment Programme.

 

Short Answers :

Question. Give scientific terms for the following- 
i. The process of eating and being eaten.
ii. The relationship between abiotic and biotic component.
iii. Increasing concentration of a non biodegradable substance, such as a toxic
chemical, in the tissues of organisms at successively higher levels in a food chain.
Answer : i. Food chain
ii. Ecosystem
iii. Bio-magnification

Question. What is a food web? Give few characteristics of a food web? Give an example of a food web?
Answer: Food web is a network of food chains which become interconnected at various trophic levels so as to form a number of feeding connections amongst different organisms of a biotic community.
Some characteristics of a food web are:
(a) Food web is an interlink of different food chains.
(b) It provides alternative pathways of food availability.
(c) Due to greater alternatives for food, it makes the ecosystem stable.
(d) It helps in development of an ecosystem.
Example of food web: 

CBSE Class 10 Science Our Environment Worksheet

Question. Describe how decomposers facilitate recycling of matter in order to maintain balance in the ecosystem?
Answer: Decomposers act upon dead and decay organisms to convert them into simpler forms. These simple substances get mixed up in the soil and are used as nutrients by the producers. From producers it goes to consumers and so on. Thus there is recycling of matter which is done by decomposers that maintain
the balance in the ecosystem.

Question. Define a food chain. Design a terrestrial food chain of four trophic levels. If a pollutant enters at the producer level, the organisms of which trophic level will have the maximum concentration of the pollutant in their bodies? What is this phenomenon called?
Answer: It is the sequence of arrangement of living organism in a community in which one organism consumes another organism to transfer food energy. 
CBSE Class 10 Science Our Environment Worksheet
The organism at higer tropic level will have the maximum concentration of pollutants. This phenomenon is called biological magnification.

Question. Give any two ways in which biodegradable substances would affect the environment.
Answer: The two ways in which biodegradable substances would affect the environment are:
(a) Decomposition of biodegradable substances results in production of foul smell.
(b) The area where biodegradable wastes are accumulated serves as a good breeding place for mosquitoes, flies etc.
which are the main carriers of germs for diseases like cholera, jaundice, typhoid etc.

Question. Give some characteristics of a food chain?
Answer: Some characteristics of food chain are:
(a) A food chain always progress in a straight chain.
(b) There is an unidirectional flow of energy from sun to producers to a series of consumers.
(c) There are 3-4 trophic levels or maximum upto 5 levels in a food chain.
(d) It helps in understanding the food relationships and interaction among various living organisms present in an ecosystem.

Question. Briefly describe different methods of wastes disposal?
Answer: The various methods of waste disposal are:
(a) Land-fills: In urban areas wastes are filled or deposited in low lying areas. These are also known as dumping grounds where wastes are buried.
(b) Recycling of wastes: Some wastes like papers, plastics, metals etc., which can be recycled are send to special recycling treatment plants so that new substances can be made from them.
(c) Preparation of compost: Biodegradable wastes like kitchen wastes, peels of fruits and vegetables etc., can be used to prepare compost which serves as a good manure to the plants.
(d) Incineration: Some wastes like medical wastes, chemical wastes are burnt at very high temperature in an incinerator and the ashes left behind are disposed by landfills.
(e) Production of biogas: Biodegradable wastes can be used in biogas plants to produce biogas which is used for several purposes like as a fuel.

Question. If all the waste we generate is biodegradable, will this have no impact on the environment? 
Answer: If all the waste we generate is biodegradable then their decomposition at right time will not be possible as number of decomposers would be less as compared to the amount of biodegradable substances. It will get accumulated in the environment causing foul smell and will form a good breeding place for flies, mosquitoes etc., which will carry many disease
causing germs. Thus various diseases like cholera, typhoid, jaundice, malaria, dengue etc., will be spread

Question. Suggest any four activities in daily life which are ecofriendly?
Answer: The four activities in daily life which are ecofriendly are:
(a) Carrying paper bags instead of polythene bags for shopping.
(b) Use of compost and biofertilisers, biopesticides instead of chemical fertilisers and pesticides.
(c) Segregating biodegradable and non-biodegradable substances and putting them in separate dustbins.
(d) Rain water harvesting.

Question. Define an ecosystem. Draw a block diagram to show the flow of energy in an ecosystem.
Answer: Ecosystem refers to the interaction of all the biotic and abiotic components present in a particular area. Energy flows across the trophic levels following the 10% law. Only 10% of the energy, available to a trophic level is passed on to the next trophic level. 

CBSE Class 10 Science Our Environment Worksheet

Question. What are the problems caused by the non-biodegradable wastes that we generate? 
Answer: The problems caused by the non-biodegradable wastes are:
(i) mulate in the soil causing pollution and also reduces the fertility of the soil.
(ii) Some pesticides like DDT, mercury etc., which are nonbiodegradable undergo biological magnification by entering into food chain.
(iii) If these substances do not undergo proper disposal techniques they will accumulate in soil thus reduces the fertility of soil.
(iv) Some harmful non-biodegradable substances may caus diseases in living organisms.

Question. What are decomposers? What will be the consequence of their absence in an ecosystem?
Answer: Decomposers are the microbes that feed on dead and decay organisms. Dead plants and animals will get accumulated in the ecosystem as there would be no decomposers to decompose them. The decomposers will act upon dead and decayed organisms into simpler forms and get mixed in the soil which is used by producers again. But in the absence of decomposers this whole process would not occur and the dead organisms will get accumulated in the ecosystem.

Question. The following organisms form a food chain. Insects, hawk, grass, snake, frog. Arrange them in proper sequence to form a food chain? Which of these will have the highest concentration of non-biodegradable chemicals? Name the phenomenon associated with it?
Answer: Grass, insects, frog, snake, hawk.
Hawk will have the highest concentration of non-biodegradable chemicals as it is placed at the top level of the food chain. This phenomenon is called Biomagnification.

Question. What are trophic levels? Give an example of food chain and state the different trophic levels in it?
Answer: The distinct sequential steps or levels in the food chain where transfer of energy occurs are referred to as trophic levels.
Example of a food chain is:
Grass → Grasshopper → Lizard → Snake → Hawk
Grass is producer, it belongs to first trophic level. Grasshopper is
primary consumer, it belongs to second trophic level. Lizard is
secondary consumer, it belongs to third trophic level. Snake is
tertiary consumer and it belongs to fourth trophic level and hawk is
quaternary consumer, it belongs to fifth trophic level.

Question. Write short note on food pyramid. 
Answer :   Food pyramid: One of the consequences of a food chain is in loss of energy at each step. The more consumers in the chain, the less energy is available at the end. If the food chain is constructed so that the number of energy contents of the producers are placed on top of this pyramid is said to be constructed. A great number of producers are needed to support a lesser number of primary consumers, which in turn can support a still lesser number of secondary consumers and still a few number of tertiary consumers as shown in figure. Thus there is loss of mass and energy at each level of a food chain and if the different trophic levels are arranged, a pyramid is constructed.

Question. Why plants are called as producers? 
Answer :  Plants are called producers, because they produce thier own food. they do this by using light energy from the sun, carbon dioxide from the air and water from the soil to produce food in the form of glucose (sugar) the process is called photosynthesis. 

 

Long Answers :

Question. Why is it difficult to draw sharp boundaries between ecosystems? 
Answer :  An ecosystem is an area in which the inputs and outputs can be studied across its boundaries are for convenience it is considered a separate entity. It is important to recognise that ecosystems are not strictly separate. Their boundaries are indistinct and overlapping and some movements always occur from one ecosystem to another in terms of energy and materials. Thus it is difficult to draw sharp boundaries between ecosystems.
Example. Leaves of riverbank trees dropping in river water represent transfer of energy and material from terrestrial to aquatic ecosystem. Terrestrial birds diving to catch fishes in water bodies make similar transfers from aquatic to terrestrial ecosystems. Soil materials may be eroded from a forest ecosystem and washed into the adjoining stream, or dust blown from a desert ecosystem may deposit over another ecosystem located miles away. 
 
Question. What are the functions of ecosystem? 
Answer :  Functions of ecosystem. Ecosystem possess a natural tendency to persist. This is made possible by a variety of functions (activities undertaken to ensure persistence) performed by the structural components. For instance, green leaves function as sites of food production, and roots absorb nutrients from the soil. Herbivores perform the function of utilizing part of the plant production, and in turn serve as food for carnivores.
Decomposers carry out the function of breaking down complex organic materials into simpler inorganic products which can be used by the producers. These functions are carried out in the ecosystem through delicately balanced and controlled processes. For example, the process of photosynthesis is involved in food production, and that of decomposition leads to release of nutrients contained in the organic matter.
The key functional aspects of the ecosystem are:
i. Productivity and energy flow
ii. Nutrient cycling
iii. Development and stabilization
 

Case Based Questions :

Refer the figure below carefully and answer the following questions. 

CBSE Class 10 Science Our Environment Worksheet

Question. After solar energy enters our atmosphere, which statement does not hold good regarding subsequent the events? 
(a) Most of the radiation is absorbed by the Earth’s surface and used to warm the surface.
(b) Some of the solar radiation is reflected by Earth and atmosphere.
(c) Some of the infra-red radiation is absorbed by the atmosphere and re-emitted in all directions by the green-house gases.
(d) No infra-red radiation is emitted by Earth.

Answer: D

Question. Energy flow diagram definitely conveys all the points given below, except: 
(a) the flow of energy is multi-directional.
(b) the energy captured by the autotrophs does not return to the solar input.
(c) the energy that passes to the herbivores does not come back to the autotrophs.
(d) the energy moves progressively through the various trophic levels and it is no longer available to the previous level.

Answer: A

Question. How are the organisms on Block 1 level best described as: 
(a) primary consumers
(b) secondary consumers
(c) tertiary consumers
(d) decomposers

Answer: A

Question. In the figure given above what would be the amount of energy available at block 1 and block 2 levels if energy at producer level is 10,000 kcal? 
(a) 1000 kcal and 100 kcal
(b) 100 kcal and 1000 kcal
(c) 10,000 kcal and 100 kcal
(d) 100 kcal and 10 kcal

Answer: A

Question. What is represented by eagle at black 3? 
(a) decomposers
(b) secondary consumers
(c) tertiary consumers
(d) predator

Answer: C

Study the figure given below carefully and answer the following questions. 

CBSE Class 10 Science Our Environment Worksheet

Question. What is the name of the interrelation shown in this figure? 
(a) Food chain
(b) Food web
(c) Trophic level
(d) Energy conservation

Answer: B

Question. The series of branching lines shown in above figure appears in nature because: 
(a) the length and complexity of food chains vary.
(b) each organism is generally eaten by two or more other kinds of organisms.
(c) straight line food chains are not practically possible.
(d) all of the above

Answer: D

Question. Which one of the following is true for a food web? 
(a) Food web does not help in stabilising the ecosystem.
(b) secondary consumers cannot feed on other species in the event of decrease in population of prey.
(c) A food web provides alternative pathways of food availability.
(d) Food webs are straight.

Answer: C

Question. The main source of energy flowing in any food web is the: 
(a) animals
(b) consumer
(c) primary producer
(d) sun

Answer: D

Question. In the picture shown above concentration of a chemical absorbed from soil is likely to be highest in: 
(a) wildflowers
(b) grass
(c) coyote
(d) rabbit

Answer: C

Read the following and answer the following questions.
The energy flow in the ecosystem is one of the major factors that support the survival of such a great number of organisms. For almost all organisms on earth, the primary source of energy is solar energy. It is amusing to find that we receive less than 50 per cent of the sun’s effective radiation on earth. When we say effective radiation, we mean the radiation, which can be used by plants to carry out photosynthesis. 1

CBSE Class 10 Science Our Environment Worksheet

Question. Which of the two sets belong to the same trophic level? 
(a) Frog : Lizard
(b) Rabbit : Tiger
(c) Vulture : Crow
(d) Deer : Hawk

Answer: A

Question. A food chain comprising birds, green plants, fish and man. The concentration of harmful chemical entering the food chain will be maximum in: 
(a) plant
(b) man
(c) birds
(d) fish

Answer: B

Question. Every food chain in the ecosystem begins with _________. Which are the original? 
(a) saprophytes
(b) parasites
(c) producers
(d) none of these

Answer: C

Question. If 100 J energy is available at the producer level in a food chain then the energy available to the secondary consumer will be: 
(a) 10 J
(b) 0.1 J
(c) 1 J
(d) 0.01 J

Answer: C

Question. The constituents which do not form eco-system are: 
(a) Biotic constituents
(b) Plastic bags
(c) Abiotic constituents
(d) All of the above

Answer: B

Chapter 16 Sustainable Management of Natural Resources
CBSE Class 10 Science Sustainable Management of Natural Resources Worksheet

More Study Material

CBSE Class 10 Science Chapter 15 Our Environment Worksheet

We hope students liked the above worksheet for Chapter 15 Our Environment designed as per the latest syllabus for Class 10 Science released by CBSE. Students of Class 10 should download in Pdf format and practice the questions and solutions given in the above worksheet for Class 10 Science on a daily basis. All the latest worksheets with answers have been developed for Science by referring to the most important and regularly asked topics that the students should learn and practice to get better scores in their class tests and examinations. Studiestoday is the best portal for Class 10 students to get all the latest study material free of cost.

Worksheet for Science CBSE Class 10 Chapter 15 Our Environment

Expert teachers of studiestoday have referred to the NCERT book for Class 10 Science to develop the Science Class 10 worksheet. If you download the practice worksheet for one chapter daily, you will get higher and better marks in Class 10 exams this year as you will have stronger concepts. Daily questions practice of Science worksheet and its study material will help students to have a stronger understanding of all concepts and also make them experts on all scoring topics. You can easily download and save all revision worksheet for Class 10 Science also from www.studiestoday.com without paying anything in Pdf format. After solving the questions given in the worksheet which have been developed as per the latest course books also refer to the NCERT solutions for Class 10 Science designed by our teachers

Chapter 15 Our Environment worksheet Science CBSE Class 10

All worksheets given above for Class 10 Science have been made as per the latest syllabus and books issued for the current academic year. The students of Class 10 can be rest assured that the answers have been also provided by our teachers for all worksheet of Science so that you are able to solve the questions and then compare your answers with the solutions provided by us. We have also provided a lot of MCQ questions for Class 10 Science in the worksheet so that you can solve questions relating to all topics given in each chapter. All study material for Class 10 Science students have been given on studiestoday.

Chapter 15 Our Environment CBSE Class 10 Science Worksheet

Regular worksheet practice helps to gain more practice in solving questions to obtain a more comprehensive understanding of Chapter 15 Our Environment concepts. Worksheets play an important role in developing an understanding of Chapter 15 Our Environment in CBSE Class 10. Students can download and save or print all the worksheets, printable assignments, and practice sheets of the above chapter in Class 10 Science in Pdf format from studiestoday. You can print or read them online on your computer or mobile or any other device. After solving these you should also refer to Class 10 Science MCQ Test for the same chapter.

Worksheet for CBSE Science Class 10 Chapter 15 Our Environment

CBSE Class 10 Science best textbooks have been used for writing the problems given in the above worksheet. If you have tests coming up then you should revise all concepts relating to Chapter 15 Our Environment and then take out a print of the above worksheet and attempt all problems. We have also provided a lot of other Worksheets for Class 10 Science which you can use to further make yourself better in Science

Where can I download latest CBSE Printable worksheets for Class 10 Science Chapter 15 Our Environment

You can download the CBSE Printable worksheets for Class 10 Science Chapter 15 Our Environment for latest session from StudiesToday.com

Can I download the Printable worksheets of Chapter 15 Our Environment Class 10 Science in Pdf

Yes, you can click on the links above and download Printable worksheets in PDFs for Chapter 15 Our Environment Class 10 for Science

Are the Class 10 Science Chapter 15 Our Environment Printable worksheets available for the latest session

Yes, the Printable worksheets issued for Class 10 Science Chapter 15 Our Environment have been made available here for latest academic session

How can I download the Class 10 Science Chapter 15 Our Environment Printable worksheets

You can easily access the links above and download the Class 10 Printable worksheets Science Chapter 15 Our Environment for each chapter

Is there any charge for the Printable worksheets for Class 10 Science Chapter 15 Our Environment

There is no charge for the Printable worksheets for Class 10 CBSE Science Chapter 15 Our Environment you can download everything free

How can I improve my scores by solving questions given in Printable worksheets in Class 10 Science Chapter 15 Our Environment

Regular revision of practice worksheets given on studiestoday for Class 10 subject Science Chapter 15 Our Environment can help you to score better marks in exams

Are there any websites that offer free test sheets for Class 10 Science Chapter 15 Our Environment

Yes, studiestoday.com provides all latest NCERT Chapter 15 Our Environment Class 10 Science test sheets with answers based on the latest books for the current academic session

Can test papers for Class 10 Science Chapter 15 Our Environment be accessed on mobile devices

Yes, studiestoday provides worksheets in Pdf for Chapter 15 Our Environment Class 10 Science in mobile-friendly format and can be accessed on smartphones and tablets.

Are worksheets for Chapter 15 Our Environment Class 10 Science available in multiple languages

Yes, worksheets for Chapter 15 Our Environment Class 10 Science are available in multiple languages, including English, Hindi