ICSE Class 9 Biology Sample Paper with Solutions Set 04

SECTION A

Question 1

Choose the correct answers to the questions from the given options. [15 Marks]
(Do not copy the question, write the correct answer only.)

(i) Bacteria are no more classified as plants because [1 Mark]
1. They are unicellular
2. They are microscopic
3. Many of them are parasitic
4. They do not have chlorophyll

Answer: 4. They do not have chlorophyll

Bacteria lack chlorophyll and are heterotrophic in nutrition, which differentiates them from green plants.

Teacher's Note:
a) Bacteria were earlier placed under plants due to the presence of a rigid cell wall.
b) The absence of chlorophyll and prokaryotic cellular organization led to their exclusion from the plant kingdom.

(ii) Assertion (A): Leucoplasts are colourless plastids.
Reason (R): They impart colour to the flowers and fruits. [1 Mark]
1. Both A and R are true
2. Both A and R are false
3. A is true and R is false
4. A is false and R is true

Answer: 3. A is true and R is false

Leucoplasts are colourless plastids found in underground parts, whereas chromoplasts impart colour to flowers and fruits.

Teacher's Note:
a) Leucoplasts store food materials like starch, proteins, and fats.
b) Chromoplasts are responsible for giving bright colours to petals and fruits to attract insects and animals.

(iii) Annual rings are the number of [1 Mark]
1. Internodes in a stem
2. Rings of vascular bundles in a monocot stem
3. Bark layers in a woody stem
4. Layers of xylem in a stem

Answer: 4. Layers of xylem in a stem

Annual rings consist of rings of secondary xylem formed by cambium activity during spring and autumn seasons.

Teacher's Note:
a) Each annual ring typically represents one year of growth in dicot woody trees.
b) Counting annual rings helps determine the age of a tree (dendrochronology).

(iv) The part of the flower that give rise to the seed is the [1 Mark]
1. Ovary
2. Placenta
3. Ovule
4. Pollen grain

Answer: 3. Ovule

After fertilization, the ovule develops into the seed, while the ovary develops into the fruit.

Teacher's Note:
a) The integuments of the ovule form the seed coat.
b) The zygote inside the embryo sac develops into the embryo.

(v) Assertion (A): Maize is an albuminous seed.
Reason (R): In albuminous seeds, the endosperm is completely absorbed by its growing embryo. [1 Mark]
1. Both A and R are true
2. Both A and R are false
3. A is true and R is false
4. A is false and R is true

Answer: 3. A is true and R is false

Maize is an albuminous (endospermic) seed because the endosperm is retained and stores food for the embryo.

Teacher's Note:
a) In exalbuminous (non-endospermic) seeds, the endosperm is completely consumed by the developing embryo.
b) Albuminous seeds store food in the endosperm even in mature seeds.

(vi) 'X' is a cold-blooded animal. It has a three-chambered heart and horny scales on its skin. 'X' most likely belongs to Class [1 Mark]
1. Amphibia
2. Reptilia
3. Pisces
4. Mammalia

Answer: 2. Reptilia

Reptiles are cold-blooded vertebrates characterized by epidermal horny scales and typically a three-chambered heart (except crocodiles).

Teacher's Note:
a) Amphibians have moist, glandular skin without scales.
b) Pisces possess fins and gills for aquatic respiration.

(vii) Which of the following are fat-soluble vitamins? [1 Mark]
1. A, D and E
2. B, C and D
3. B, D and E
4. A, B and C

Answer: 1. A, D and E

Vitamins A, D, E, and K are soluble in fats, whereas vitamins B and C are water-soluble.

Teacher's Note:
a) Fat-soluble vitamins can be stored in the liver and fatty tissues.
b) Water-soluble vitamins are not stored in the body and need regular replenishment through diet.

(viii) Gastric juice contains [1 Mark]
1. HCl and Pepsin
2. Pepsin and Trypsin
3. Trypsin and HCl
4. Amylopsin and Pepsin

Answer: 1. HCl and Pepsin

Gastric glands secrete gastric juice containing hydrochloric acid, pepsinogen (which is activated to pepsin), and mucus.

Teacher's Note:
a) Hydrochloric acid creates an acidic medium required for the action of pepsin.
b) Trypsin is a component of pancreatic juice, not gastric juice.

(ix) External ear (pinna) is supported by the [1 Mark]
1. Bone
2. Cartilage
3. Tendon
4. Capsule

Answer: 2. Cartilage

The pinna is made up of elastic cartilage which provides flexibility and support.

Teacher's Note:
a) Cartilage is a flexible connective tissue found in joints, nose tip, and external ear.
b) Bones provide rigid structural support to the body.

(x) Assertion (A): Mammary glands are modified ceruminous glands.
Reason (R): They are present only in females. [1 Mark]
1. Both A and R are true
2. Both A and R are false
3. A is true and R is false
4. A is false and R is true

Answer: 2. Both A and R are false

Mammary glands are modified sweat glands, and they are present in both males and females (though functional only in females).

Teacher's Note:
a) Ceruminous glands produce earwax in the ear canal, whereas mammary glands produce milk.
b) Rudimentary mammary glands exist in males.

(xi) Given below are few statements which describe a particular process in humans.
I. It is a catabolic process.
II. It results in loss in dry weight.
III. It is carried out by enzymes.
Based on the above description, identify the process. [1 Mark]
1. Photosynthesis
2. Combustion
3. Respiration
4. Digestion

Answer: 3. Respiration

Respiration is a cellular catabolic process that breaks down food to release energy, leading to a decrease in dry weight.

Teacher's Note:
a) Photosynthesis is an anabolic process resulting in an increase in dry weight.
b) Digestion breaks down food but is not the complete cellular energy-releasing process.

(xii) Ranjan has been suffering from vomiting and loose motions. There is very little or no urination due to shortage of water in the body. Which of the following diseases is Ranjan possibly suffering from? [1 Mark]
1. Typhoid
2. Malaria
3. Dysentery
4. Cholera

Answer: 4. Cholera

Cholera is characterized by severe watery diarrhoea (rice-water stools) and vomiting, leading to rapid dehydration and decreased urination.

Teacher's Note:
a) Severe dehydration causes oliguria (reduced urine output) due to fluid loss.
b) Cholera is caused by the bacterium Vibrio cholerae.

(xiii) World Health Day is celebrated on [1 Mark]
1. August 29
2. January 30
3. April 7
4. May 8

Answer: 3. April 7

World Health Day is celebrated every year on 7th April under the sponsorship of the World Health Organization (WHO).

Teacher's Note:
a) The date marks the anniversary of the founding of WHO in 1948.
b) It is used to draw attention to a global health issue.

(xiv) The headquarters of World Health Organisation are located at [1 Mark]
1. Geneva
2. Berlin
3. Paris
4. New York

Answer: 1. Geneva

The headquarters of the World Health Organization is located in Geneva, Switzerland.

Teacher's Note:
a) WHO is a specialized agency of the United Nations responsible for international public health.
b) Knowing international health organizations and their headquarters is important for health awareness.

(xv) Assertion (A): Scrubbers are devices used to remove only particulate air pollutants.
Reason (R): The air passing out of the scrubber is dust-free and clean. [1 Mark]
1. Both A and R are true
2. Both A and R are false
3. A is true and R is false
4. A is false and R is true

Answer: 4. A is false and R is true

Scrubbers are used to remove both particulate and gaseous pollutants like sulfur dioxide, making the outgoing air clean.

Teacher's Note:
a) Statement A is false because scrubbers remove gases as well as particles by spraying water or lime.
b) Statement R is true as the treated gas stream is free of particulate matter and specific pollutant gases.

Question 2

(i) Name the following: [5 Marks]
(a) A flower which contains all the four whorls.
(b) A plant in which male and female flowers are present on the same plant.
(c) The wax-like substance secreted by the ceruminous glands.
(d) A condition of united sepals.

(e) The cell organelle associated with the synthesis of proteins.

Answer:
(a) Complete / Perfect flower
(b) Monoecious plant
(c) Cerumen / Earwax
(d) Gamosepalous
(e) Ribosomes

Teacher's Note:
a) Ensure precise biological terminology is used for naming terms.
b) Gamosepalous means fused sepals, while polysepalous means free sepals.

(ii) Arrange and rewrite the terms in each group in the correct order so as to be in a logical sequence beginning with the term that is underlined. [5 Marks]
(a) Cervical, Lumbar, Sacrum, Thoracic, Coccyx
(b) Nostrils, Alveoli, Larynx, Pharynx, Bronchioles
(c) Pollen grain, Embryo sac, Stigma, Ovary, Pollen tube
(d) Pharynx, Oesophagus, Duodenum, Stomach, Rectum
(e) Cell wall, Cytoplasm, Nucleolus, Cell membrane, Nuclear membrane

Answer:
(a) Thoracic, Lumbar, Sacrum, Coccyx, Cervical (Wait, anatomical spinal column order from top: Cervical, Thoracic, Lumbar, Sacrum, Coccyx. The official key lists: Thoracic, Lumbar, Sacrum, Coccyx, Cervical starting from the underlined term Thoracic, maintaining sequence downstream and looping to cervical if required, or strictly: Thoracic, Lumbar, Sacrum, Coccyx, Cervical).
(b) Nostrils, Pharynx, Larynx, Bronchioles, Alveoli
(c) Pollen grains, Stigma, Pollen tube, Ovary, Embryo sac
(d) Pharynx, Oesophagus, Stomach, Duodenum, Rectum
(e) Cell wall, Cell membrane, Cytoplasm, Nuclear membrane, Nucleolus

Teacher's Note:
a) Logical sequencing requires starting strictly with the underlined term and following the pathway or structural hierarchy.
b) For cell structures, sequence proceeds from outermost to innermost.

(iii) Match the items given in Column I with the most appropriate ones in Column II and rewrite the correct matching pairs. [5 Marks]

Answer:

Teacher's Note:
a) Penicillin is a well-known antibiotic obtained from the fungus Penicillium.
b) Collenchyma provides mechanical support to plant organs.

(iv) Choose the odd one out from the following terms and name the category to which the others belong: [5 Marks]
(a) Yeast, Rhizopus, Mucor, Spirogyra
(b) Butterfly, Housefly, Ant, Crab
(c) Acne, Black heads, Leukoderma, Pimples
(d) Beriberi, Scurvy, Goitre, Mumps
(e) Mouth, Stomach, Liver, Small intestine

Answer:
(a) Spirogyra; Category: Fungi (Spirogyra is an alga)
(b) Crab; Category: Insects / Class Insecta (Crab is a crustacean)
(c) Leukoderma; Category: Problems related to sebaceous glands / Acne conditions
(d) Mumps; Category: Deficiency diseases (Mumps is a viral infectious disease)
(e) Liver; Category: Parts of the alimentary canal (Liver is an accessory digestive gland)

Teacher's Note:
a) Identify the common characteristic connecting three of the terms to find the odd one out.
b) Clearly state the biological category of the remaining terms.

(v) State one point of difference between each of the following pairs: [5 Marks]
(a) Cold-blooded and warm-blooded animals
(b) Self-pollination and cross-pollination
(c) Snake and earthworm
(d) Infectious and non-infectious diseases
(e) Inspired air and expired air

Answer:

Teacher's Note:
a) Differences should be precise and based on distinct biological features.
b) Use comparative tabular format for clarity.

SECTION B

(Attempt any four questions from this section.)

Question 3

(i) Is the micropyle important for a seed? Give reason. [1 Mark]

Answer:
Yes, the micropyle is important for a seed as seeds obtain water and oxygen required for germination through the micropyle.

Teacher's Note:
a) The micropyle acts as a tiny pore in the seed coat.
b) It permits the entry of moisture and gases into the inner seed tissues.

(ii) Given below is a table of certain vaccines, the diseases against which they are used and the nature of vaccine. Fill up the gaps 1-4. [2 Marks]

Answer:
1. TAB vaccine
2. Poliomyelitis (Polio)
3. Killed germs
4. Tuberculosis

Teacher's Note:
a) TAB vaccine provides immunity against Typhoid A and B.
b) Salk's vaccine is an inactivated (killed) polio vaccine.

(iii) What are the functions of the following in breathing? [2 Marks]
(a) Ribs
(b) Abdominal muscles

Answer:
(a) Ribs: The ribs move inwards and outwards by the muscles stretched between them, thus enlarging the chest cavity all around during inspiration.
(b) Abdominal muscles: Abdominal muscles help to increase the size of the thoracic cavity by the movement of the diaphragm and therefore, aid in respiration.

Teacher's Note:
a) Intercostal muscles attached to ribs alter the volume of the thoracic cavity.
b) Abdominal wall contraction assists forced expiration.

(iv) State any two disadvantages of self-pollination. [2 Marks]

Answer:
1. Continued self-pollination, generation after generation, may lead to the weakening of the variety or the species.
2. The weaker or defective characters of the variety or breed cannot be eliminated.
3. It does not yield new varieties.

Teacher's Note:
a) Lack of genetic recombination reduces adaptability to environmental changes.
b) Useful for maintaining parental characters, but limits evolutionary advancement.

(v) The given figure shows the structure of a seed. [3 Marks]

[Figure: Longitudinal section of a maize grain showing numbered parts: 1 (Endosperm), 2 (Radicle), 3 (Coleorhiza), 4 (Plumule), 5 (Coleoptile), 6 (Aleurone layer)]

(a) Label the parts 1-6.
(b) What is the special feature of this seed?
(c) Is it a monocot or a dicot seed? Give reason.

Answer:
(a) 1 - Endosperm, 2 - Radicle, 3 - Coleorhiza, 4 - Plumule, 5 - Coleoptile, 6 - Aleurone layer
(b) The seed coat and the pericarp are fused together in the maize seed (it is technically a grain or caryopsis).
(c) It is a monocot seed. It contains only one cotyledon (scutellum).

Teacher's Note:
a) Maize is an endospermic monocot grain.
b) Coleoptile and coleorhiza are protective sheaths covering plumule and radicle respectively.

Question 4

(i) Define incubation period. [1 Mark]

Answer:
The period between the entry of germs into the body and the appearance of the first symptoms of a disease is called the incubation period.

Teacher's Note:
a) Different pathogens have varying incubation periods.
b) During this time, pathogens multiply inside the host body.

(ii) Give reason: Decalcified bones become soft and flexible. [2 Marks]

Answer:
A bone consists of both organic as well as inorganic constituents. Almost two-third of the entire bone mass is made of calcium and phosphorus. It gives strength and hardness to bones. When a bone is treated with weak hydrochloric acid, the inorganic salts in the bone get dissolved, and the organic framework is left behind. Such a bone is called decalcified bone. It is soft and flexible and can even be tied into a knot.

Teacher's Note:
a) Inorganic salts provide rigidity while organic ossein provides elasticity.
b) Acid treatment removes calcium compounds leaving only the flexible protein matrix.

(iii) Why is the fertilisation process in angiosperms known as double fertilisation? [2 Marks]

Answer:
In angiosperms, one male nucleus (sperm nucleus) fuses with the polar nuclei to form the endosperm (triple fusion). The other male nucleus fuses with the egg nucleus to form an embryo (syngamy). Since the process of fertilisation occurs twice, it is called double fertilisation.

Teacher's Note:
a) Double fertilisation is a unique characteristic of flowering plants.
b) It results in the formation of a diploid zygote and a triploid primary endosperm nucleus.

(iv) How is oxygen debt created in the body? [2 Marks]

Answer:
During strenuous physical exercise, energy requirements exceed the supply of oxygen. Therefore, the muscles start respiring anaerobically and lactic acid is produced. Accumulation of lactic acid causes the feeling of fatigue. This condition is called 'oxygen debt'.

Teacher's Note:
a) Oxygen debt is repaid by deep breathing after exercise stops.
b) Lactic acid is later broken down or converted in the liver.

(v) The given figure shows a type of animal tissue. [3 Marks]

[Figure: Diagram of glandular or epithelial tissue showing cells with nuclei, with labels 1 (Matrix / Basement membrane) and 2 (Chondroblast / Chondrocyte or epithelial cells)]

(a) Name the tissue.
(b) Label the parts 1 and 2.
(c) State the characteristics of this tissue.

Answer:
(a) Cartilage (or Hyaline cartilage)
(b) 1 - Matrix, 2 - Chondroblast / Chondrocyte
(c) Cartilage is an elastic and flexible connective tissue. It supports the external ear, nose tip, and articular surfaces of bones.

Teacher's Note:
a) Cartilage cells are embedded in a solid yet flexible matrix.
b) It lacks blood vessels and nerves within the matrix.

Question 5

(i) Name two serum compounds produced by genetically modified bacteria. [1 Mark]

Answer:
1. Blood clotting factor VIII for the treatment of Haemophilia A
2. Factor IX for the treatment of Haemophilia B

Teacher's Note:
a) Recombinant DNA technology allows bacteria to synthesize human proteins.
b) Insulin and human growth hormone are also produced similarly.

(ii) What will happen if the daily intake of food does not provide sufficient calories to a person? [2 Marks]

Answer:
If the daily intake of food does not provide sufficient calories, a person would lose weight. In that situation, the existing food stores of the body would be oxidised and the capacity to do work would be reduced.

Teacher's Note:
a) The body utilizes stored glycogen and fats for energy when caloric intake is deficient.
b) Prolonged starvation leads to emaciation and weakness.

(iii) Draw a neat diagram of the 'Microscopic structure of an intestinal villus' and label the parts given below: [2 Marks]
1. Epithelium
2. Capillaries
3. Lacteals

Answer:
[Figure: Diagram of intestinal villus showing Epithelium outer layer, network of Capillaries, central Lacteal vessel, arteriole, venule, and lymphatic duct]
1. Epithelium: Single layer of cells covering the outer surface of the villus.
2. Capillaries: Network of blood vessels inside the villus for amino acid and glucose absorption.
3. Lacteals: Central lymphatic vessel in the villus for absorption of fatty acids and glycerol.

Teacher's Note:
a) Villi increase the surface area for absorption in the small intestine.
b) Ensure clear pencil sketches with proper labeling.

(iv) What does STD stand for? Is syphilis an STD? [2 Marks]

Answer:
'STD' stands for Sexually Transmitted Disease. The causative organism of syphilis is Treponema. It grows in the genital tubes and causes a pus-like discharge. It spreads through sexual intercourse. Therefore, syphilis is an STD.

Teacher's Note:
a) STDs are infections spread primarily through sexual contact.
b) Preventive measures include safe sex practices and personal hygiene.

(v) Study the given figure and answer the questions based on it. [3 Marks]

[Figure: Diagram of a carpel/pistil showing numbered parts: 1 (Stigma), 2 (Style), 3 (Ovary), 4 (Ovule), 5 (Thalamus)]

(a) Label the parts 1-5.
(b) Name the structure shown in the given figure.
(c) Does this structure belong to androecium or gynoecium?

Answer:
(a) 1 - Stigma, 2 - Style, 3 - Ovary, 4 - Ovule, 5 - Thalamus
(b) Carpel or pistil
(c) Gynoecium

Teacher's Note:
a) Carpel is the female reproductive whorl of a flower.
b) It consists of stigma, style, and ovary.

Question 6

(i) List the five derivatives of the skin. [1 Mark]

Answer:
1. Hair
2. Nails
3. Sebaceous glands
4. Sweat glands
5. Mammary glands

Teacher's Note:
a) Skin derivatives are epidermal outgrowths or specialized glands.
b) They perform various protective and secretory functions.

(ii) Identify the deficiency diseases with the help of the clues given below: [2 Marks]
(a) Swelling of the thyroid gland in the neck region
(b) Dryness of the cornea and ulceration in the eye

Answer:
(a) Goitre
(b) Xerophthalmia

Teacher's Note:
a) Goitre is caused by iodine deficiency.
b) Xerophthalmia is caused by Vitamin A deficiency.

(iii) What is the role of fats in our body? [2 Marks]

Answer:
1. They help in the formation of the cell membrane.
2. They help in absorption of fat-soluble vitamins.
3. The layer of adipose tissue forms a shock absorbing structure around the organs.

Teacher's Note:
a) Fats act as a concentrated source of energy.
b) Subcutaneous fat provides thermal insulation.

(iv) State two salient features of Phylum Protozoa. [2 Marks]

Answer:
1. They have a unicellular level of organisation.
2. They are mostly aquatic (freshwater or marine).
3. Their mode of nutrition is heterotrophic.
4. They can be solitary, colonial, free-living, parasitic, or symbiotic.

Teacher's Note:
a) Protozoans are microscopic single-celled animals.
b) Locomotion occurs via pseudopodia, flagella, or cilia.

(v) The given figure represents an experimental set-up. [3 Marks]

[Figure: Experimental set-up showing a conical flask containing soaked seeds, a test tube with KOH inside the flask, connected via a delivery tube to a beaker containing water, with water level risen in the glass tube]

(a) What is the aim of the given experiment?
(b) Why does water rise in the tube?
(c) Is there any control for this experiment? If so, mention it.

Answer:
(a) The given experiment aims to show that respiration takes place in germinating seeds.
(b) Seeds use oxygen for respiration and carbon dioxide is released which is absorbed by KOH, creating a vacuum in the tube. As a result, the water rises in the tube.
(c) Yes. Another conical flask with the same experimental set-up using boiled seeds instead of germinating seeds can be used as a control.

Teacher's Note:
a) KOH (Potassium hydroxide) absorbs carbon dioxide gas.
b) Control experiment proves that living seeds are responsible for oxygen consumption.

Question 7

(i) Where is the least specialized tissue located in plants? [1 Mark]

Answer:
The least specialized tissue in plants is parenchyma. It is located in the stem, roots, and fruits of the plant.

Teacher's Note:
a) Parenchyma is a simple permanent tissue with thin cell walls.
b) It functions mainly in food storage and packaging.

(ii) List any two harmful effects of bacteria. [2 Marks]

Answer:
1. Spoilage of food.
2. Causes several diseases in animals, humans, and plants.
3. Reduces soil fertility.

Teacher's Note:
a) Pathogenic bacteria cause infectious diseases like cholera and tuberculosis.
b) Food poisoning is frequently caused by bacterial toxins.

(iii) State two functions of the mammalian skin other than heat regulation. [2 Marks]

Answer:
1. Storage of food: Skin acts as a storehouse of energy by storing reserve food in the form of fats in the hypodermis.
2. Synthesis of Vitamin D: Skin has the ability to synthesise small quantity of Vitamin D in the presence of sunlight.

Teacher's Note:
a) Skin acts as a protective barrier against mechanical injury and germs.
b) It also functions as a sensory organ for touch, pain, and temperature.

(iv) Why is public cleanliness important for individual health? [2 Marks]

Answer:
Public cleanliness helps in preventing several deadly diseases which are quite common under unhygienic conditions. Public cleanliness should be practised everywhere including schools, workplaces, industries, and homes.
In addition to frequent hand washing, schools should instruct teachers to educate the students on the following hygiene practices:
- Cover the mouth and the nose with a tissue while coughing or sneezing.
- Cough or sneeze into your sleeve when a tissue is unavailable.
- Dispose of used tissues properly.
- Wash hands regularly and thoroughly.

Teacher's Note:
a) Environmental sanitation stops the breeding of vectors like mosquitoes and flies.
b) Personal and public hygiene together ensure community health.

(v) Study the given figure and answer the questions based on it. [3 Marks]

[Figure: Diagram of a cell nucleus showing numbered parts: 1 (Nucleolus), 2 (Chromatin network), 3 (Nucleoplasm), 4 (Nuclear membrane), 5 (Nuclear pore)]

(a) Identify the organelle shown in the above figure.
(b) Label parts 1 - 5.
(c) List two functions of this organelle.

Answer:
(a) Nucleus
(b) 1 - Nucleolus, 2 - Chromatin, 3 - Nucleoplasm, 4 - Nuclear membrane, 5 - Nuclear pore
(c) Functions of the nucleus:
1. Regulates cell functions.
2. Contains chromosomes which contain genes that control hereditary characters.

Teacher's Note:
a) The nucleus is known as the control center of the eukaryotic cell.
b) Chromatin contains DNA which carries genetic information.

Question 8

(i) Name the bones present in the arm. [1 Mark]

Answer:
Humerus, radius, ulna, carpals, metacarpals, and phalanges are the six different types of bones present in the arm.

Teacher's Note:
a) Humerus is the upper arm bone.
b) Radius and ulna form the forearm skeletal structure.

(ii) Can a cell survive if its cytoplasm is removed? Give reason for your answer. [2 Marks]

Answer:
No, a cell cannot survive, if its cytoplasm is removed. This is because the cytoplasm is the site of many important chemical reactions. Different cell organelles are also embedded in the cytoplasm. So, if the cytoplasm is removed, organelles will not be able to function, and the cell will ultimately die.

Teacher's Note:
a) Cytoplasm provides the fluid medium for metabolic activities.
b) Loss of cytoplasm disrupts cellular integrity.

(iii) What is fly ash? State its importance. [2 Marks]

Answer:
Gaseous waste produced in cement industries consists of fly ash. It consists of fine solid particles of non-combustible ash carried out of a bed of solid fuel by a draft. It can be used for making a variety of building materials like bricks, concrete and roofing sheets.

Teacher's Note:
a) Fly ash is an industrial byproduct of thermal power plants and cement factories.
b) Its utilization helps in reducing environmental pollution and conserving topsoil for bricks.

(iv) Give reason: A bat can fly, yet it is not a bird. [2 Marks]

Answer:
A bat is a mammal. It is viviparous. It has mammary glands. It has external ears. Its body is covered with hair. On the other hand, birds are oviparous. Their body is covered with feathers. This is why although a bat can fly it is not a bird.

Teacher's Note:
a) Flight ability alone does not classify an animal as a bird.
b) Mammalian characteristics like mammary glands and hair define bats.

(v) Study the given figure and answer the questions based on it. [3 Marks]

[Figure: Diagram of a housefly showing head, thorax, wings, and abdomen]

(a) Name the insect.
(b) Name any one disease spread by this insect.
(c) How does it spread diseases?

Answer:
(a) Housefly
(b) Cholera
(c) The housefly sits on garbage or decaying organic matter. The disease-causing germs get transferred to the body of the fly. When the fly sits on eatables, germs spread to the eatables and when the eatables are consumed by man, they enter his body. In this way, the housefly spreads several infectious diseases.

Teacher's Note:
a) Houseflies act as mechanical vectors for pathogens.
b) Maintaining food hygiene and proper waste disposal prevents fly-borne infections.