CBSE Class 7 Science Revision Worksheet Set 11

Based on the topic: 1-Nutrition in plants, 2-Animal fibers, 3-Weather climate & adaptation, 4-Soil

Q1. Multiple choices Question:-

Question 1. Which of the following is a saprotroph?
(a) Mushroom
(b) pea
(c) Wheat
Answer: (a) Mushroom
Mushrooms feed on dead and decaying matter, which is the characteristic feature of saprotrophs.
In simple words: Saprotrophs are organisms that feed on dead and rotting things like mushrooms.

Exam Tip: Remember that green plants are autotrophs, and mushrooms are fungi that act as saprotrophs.

Question 2. Sorters disease is caused by
(a) larva of silk moth
(b) handling of cocoon
(c) Anthrax bacterium Point out the Name N
Answer: (c) Anthrax bacterium
Anthrax is a fatal blood disease caused by the bacterium Bacillus anthracis, which affects wool sorters.
In simple words: Workers sorting wool can catch anthrax disease from bacteria present in infected fleece.

Exam Tip: Wool sorters disease is a classic example of an occupational hazard caused by bacteria.

Question 3. Name a migratory bird?
(a) Toucan
(b) Penguin
(c) Siberian crane
(d) both b and c
Answer: (c) Siberian crane
Siberian cranes migrate from Siberia to warmer regions like India during winters to escape harsh cold.
In simple words: Siberian cranes fly long distances to escape extreme cold weather.

Exam Tip: Penguins live in polar regions permanently and do not migrate like Siberian cranes.

Question 4. The best soil for growing crops
(a) clayey soil
(b) sandy soil
(c) loamy soil
(d) all of these
Answer: (c) loamy soil
Loamy soil is a mixture of sand, silt, and clay with the right water retention and aeration capacity for plant growth.
In simple words: Loamy soil holds the right amount of water and air, making it best for crops.

Exam Tip: Clay holds too much water and sandy holds too little; loam is the balanced combination.

Question 5. Cuscuta exhibits _____ mode of nutrition
(a) Parasite
(b) Saprotrophic
(c) Symbiotic
(d) none of these
Answer: (a) Parasite
Cuscuta (Amarbel) is a parasitic plant that climbs on a host plant to derive ready-made nutrients.
In simple words: Cuscuta steals food from other plants as a parasite.

Question 6. Identify the animal that does not yield wool:
(a) Donkey
(b) Camel
(c) Sheep
(d) Goat
Answer: (a) Donkey
Sheep, goats, and certain breeds of camels yield wool or hair used for textiles, whereas donkeys do not.
In simple words: Donkeys do not have woolly hair used for making wool fabrics.

Exam Tip: Wool-yielding animals generally have a thick coat of hair called fleece.

Question 7. Identify the thermometer used for measuring maximum and minimum temperatures in a day
(a) Digital thermometer
(b) clinical thermometer
(c) laboratory thermometer
(d) maximum and minimum thermometer
Answer: (d) maximum and minimum thermometer
Maximum and minimum thermometers are specially designed to record the highest and lowest temperatures of the day.
In simple words: A maximum-minimum thermometer records weather extremes.

Exam Tip: Clinical thermometers are for human body temperature, and laboratory thermometers are for science experiments.

Question 8. Which of the following does not support weathering?
(a) Rotting
(b) wind
(c) water
(d) climate
Answer: (a) Rotting
Wind, water, and climate are the primary agents of physical and chemical weathering of rocks, whereas rotting is decomposition.
In simple words: Wind, water, and climate break down rocks, while rotting does not break rocks into soil.

Exam Tip: Weathering is the breaking down of rocks at Earth's surface by physical and chemical agents.

Question 9. Name the Organisms which manufacture their own food
(a) heterotrophs
(b) omnivores
(c) herbivores
(d) autotrophs
Answer: (d) autotrophs
Organisms that prepare their own food from simple inorganic substances using light energy are called autotrophs.
In simple words: Green plants make their own food and are called autotrophs.

Exam Tip: 'Auto' means self and 'troph' means nourishment.

Question 10. Which of the following describes the tropical region?
(a) moderate rainfall
(b) hot and humid
(c) hot and dry
(d) cold and humid
Answer: (b) hot and humid
Tropical regions are generally characterized by hot temperatures and high humidity due to proximity to the equator.
In simple words: Tropical regions stay warm and damp throughout the year.

Exam Tip: Tropical rainforests are located in these hot and humid regions.

Q2. Give very short answer for the following question:-

Question 1. Name two products of photosynthesis?
Answer: Glucose (food/carbohydrate) and Oxygen.
In simple words: Plants produce food and oxygen during photosynthesis.

Exam Tip: Carbon dioxide and water are raw materials, while glucose and oxygen are products.

Question 2. Name any two varities of silk?
Answer: Mulberry silk and Tassar silk (or Eri silk, Muga silk).
In simple words: Mulberry and Tassar are common types of silk.

Question 3. Name the govt department in India that makes weather predictions?
Answer: The India Meteorological Department (IMD).
In simple words: The Meteorological Department predicts weather in India.

Exam Tip: IMD collects data on temperature, wind, and rainfall to prepare weather reports.

Question 4. Name three ways of controlling soil pollution?
Answer:
1. Reducing the use of plastics and polythene bags.
2. Minimizing the use of chemical fertilizers and pesticides.
3. Proper treatment of industrial wastes before disposal.
In simple words: Stop using excess plastics, reduce chemical fertilizers, and treat factory waste to control soil pollution.

Exam Tip: Afforestation (planting trees) is also a major way to prevent soil erosion and pollution.

Q3. Give short answers for the following questions

Question 1. Define nutrients?
Answer: Nutrients are essential components of food such as carbohydrates, proteins, fats, vitamins, and minerals that living organisms require for body growth, repair, maintenance, and energy.
In simple words: Nutrients are the useful substances in food that give us energy and help us grow.

Exam Tip: Mention the specific categories of nutrients (carbohydrates, proteins, fats, vitamins, minerals) for full marks.

Question 2. What do you understand by percolation?
Answer: Percolation is the downward movement or filtration of water through the soil spaces and pores. Percolation rate refers to the volume of water (in mL) that passes through a given soil sample per unit of time (in minutes).
In simple words: Percolation is how fast water seeps down through soil layers.

Exam Tip: Formula for percolation rate = Amount of water (mL) / Percolation time (min).

Question 3. What are Polar Regions?
Answer: Polar regions are areas situated near the Earth's North Pole and South Pole. These regions are extremely cold throughout the year, covered with thick snow and ice, and experience extreme day and night cycles lasting for months.
In simple words: Polar regions are the freezing cold areas at the very top and bottom of the Earth.

Question 4. Define pupa?
Answer: Pupa is the inactive, resting developmental stage in the life cycle of a silk moth (or other insects with complete metamorphosis) that occurs between the caterpillar ( larva) and the adult moth.
In simple words: Pupa is the resting stage where the caterpillar transforms inside a cocoon into an adult moth.

Exam Tip: Inside the pupa, dramatic changes take place to form the adult insect structure.

Question 5. Name the structures responsible for supplying water and food to various parts of plant?
Answer:
1. Xylem: Responsible for transporting water and dissolved minerals from the roots to the leaves and other parts of the plant.
2. Phloem: Responsible for transporting synthesized food (glucose/nutrients) from the leaves to all other parts of the plant.
In simple words: Xylem carries water, and phloem carries food.

Exam Tip: Think 'X' for Xylem (water eXpression/transport) and 'Ph' for Phloem (food/photosynthesis products).

Question 6. What is reeling?
Answer: Reeling is the process of taking out threads or silk filaments from the gathered cocoons to use as silk fiber. The cocoons are first boiled or exposed to steam to loosen the silk threads.
In simple words: Reeling is unwinding silk threads from cocoons to make silk yarn.

Exam Tip: Reeling is done using special machines that unwind the delicate continuous silk filaments.

Q4. Give long answers for the following questions:

Question 1. Draw and label diagram of plant showing that glucose is synthesized from carbon dioxide and water in presence of sunlight and chlorophyll?
Answer:
During photosynthesis, green plants absorb carbon dioxide from the air through stomata and water from the soil through roots. Chlorophyll traps solar energy from sunlight in the leaves. Using this energy, plants convert carbon dioxide and water into glucose (food) and release oxygen gas into the atmosphere.
In simple words: Plants use sunlight, water, carbon dioxide, and green pigment (chlorophyll) in leaves to make food and oxygen.

Exam Tip: Draw a clean diagram showing a plant with arrows indicating sunlight entering leaves, carbon dioxide entering stomata, water absorbed by roots, and oxygen being released.

Question 2. Explain in steps SOIL AS A NATURAL RESOURCE?
Answer:
Soil is considered a vital natural resource due to the following reasons and steps of formation:
1. Basis of Agriculture: Soil provides anchorage to plant roots and supplies essential water and mineral nutrients required for crop production and food security.
2. Habitat for Organisms: Soil supports numerous microorganisms, earthworms, insects, and burrowing animals that maintain soil fertility and aeration.
3. Water Storage and Filtration: Soil acts as a natural reservoir that absorbs rainwater, recharges groundwater tables, and filters impurities.
4. Raw Material: Soil is extensively used as a raw material for making bricks, pottery, and construction materials.
In simple words: Soil is essential because it helps plants grow, stores water, provides homes for tiny creatures, and supports life on Earth.

Exam Tip: Emphasize that soil formation takes thousands of years through weathering of rocks, making conservation of soil extremely important.