ICSE Class 8 Biology Sample Paper with Solutions Set 02

Question 1

Choose the correct answer out of the four available choices given below each question. [15]

1. Combining the stem and buds of two best quality plants is called_________. [1 Mark]
(a) Cutting
(b) Grafting
(c) Layering
(d) Tissue culture

Answer: (b) Grafting

Grafting is a method of artificial vegetative propagation where a scion is joined to a rooted stock.

Teacher's Note:
a) Grafting combines desirable characteristics of two different plants into a single plant.
b) Students often confuse grafting with layering; remember that grafting involves joining two separate plant parts.

2. Observe the given food chain.
Green plants → Grasshopper → Frog → Eagle
In the given food chain, the herbivore is [1 Mark]
(a) Frog
(b) Grasshopper
(c) Eagle
(d) Green plants

Answer: (b) Grasshopper

The grasshopper directly feeds on green plants (producers), making it a primary consumer or herbivore.

Teacher's Note:
a) Herbivores occupy the second trophic level in a food chain as primary consumers.
b) Always trace the arrows correctly from producer to top carnivore while answering food chain questions.

3. An embryo of a seed consists of __________. [1 Mark]
(a) Radicle, Plumule, Cotyledons
(b) Radicle and Plumule
(c) Radicle and Cotyledons
(d) Radicle, Plumule and Embryonal axis

Answer: (a) Radicle, Plumule, Cotyledons

The seed embryo comprises the embryonal axis (radicle and plumule) along with cotyledons which store food.

Teacher's Note:
a) The radicle gives rise to the root system, while the plumule develops into the shoot system.
b) Cotyledons provide nourishment to the growing embryo during germination.

4. In which of the following emergencies, a tourniquet is tied? [1 Mark]
(a) Burns
(b) Bleeding
(c) Snake bite
(d) Heart attack

Answer: (c) Snake bite

A tourniquet is tied tightly above the wound in a snake bite to prevent the spread of venom into the bloodstream.

Teacher's Note:
a) A tourniquet restricts blood flow and should be used cautiously as a temporary emergency measure.
b) Do not confuse this with general bleeding where direct pressure is applied instead of a tourniquet.

5. Leishmania donovani is the causative agent for________. [1 Mark]
(a) Sleeping sickness
(b) Athlete's foot
(c) Kala-azar
(d) Measles

Answer: (c) Kala-azar

Kala-azar (visceral leishmaniasis) is caused by the protozoan parasite Leishmania donovani.

Teacher's Note:
a) Leishmania is transmitted by the bite of infected sandflies.
b) Memorize the specific causative organisms and their corresponding vector-borne diseases.

6. Ringworm is caused by [1 Mark]
(a) Bacteria
(b) Fungi
(c) Protozoa
(d) Virus

Answer: (b) Fungi

Ringworm is a common fungal infection of the skin characterized by ring-shaped red patches.

Teacher's Note:
a) Despite its name, ringworm is not caused by a worm but by dermatophytic fungi.
b) Fungal infections thrive in warm and moist environments.

7. Evergreen broad-leaved trees are characteristic of [1 Mark]
(a) Tropical rainforests
(b) Temperate deciduous forests
(c) Coniferous forests
(d) Deserts

Answer: (a) Tropical rainforests

Heavy rainfall and high temperatures in tropical rainforests support dense growth of evergreen broad-leaved trees.

Teacher's Note:
a) Evergreen trees do not shed all their leaves simultaneously, maintaining green foliage year-round.
b) Relate plant adaptations directly to climatic conditions of different biomes.

8. ________________ is required for the synthesis of thyroxine. [1 Mark]
(a) Calcium
(b) Iron
(c) Iodine
(d) Potassium

Answer: (c) Iodine

Iodine is an essential trace element required by the thyroid gland to produce the hormone thyroxine.

Teacher's Note:
a) Deficiency of iodine leads to enlargement of the thyroid gland, known as simple goitre.
b) Iodine deficiency disorders are prevented by using iodized salt in the diet.

9. The eggs of fishes are kept in a ______ for developing into fry. [1 Mark]
(a) Nursery tank
(b) Rearing tank
(c) Small tank
(d) Stocking pound

Answer: (a) Nursery tank

Fish hatcheries use separate nursery tanks where eggs hatch safely away from predatory large fish.

Teacher's Note:
a) Nursery tanks provide a controlled environment optimized for hatching and early survival.
b) Understand the difference between nursery tanks, rearing tanks, and stocking ponds in pisiculture.

10. Universal donors belong to the blood group________ [1 Mark]
(a) AB
(b) A
(c) O
(d) B

Answer: (c) O

Individuals with blood group O lack both A and B antigens on their red blood cells, making them universal donors.

Teacher's Note:
a) Blood group AB is known as the universal recipient because it lacks antibodies against A and B.
b) Always distinguish clearly between antigens present on RBCs and antibodies present in plasma.

11. If the xylem vessels of a plant are plugged______________. [1 Mark]
(a) The leaves will turn yellow
(b) No food will be made
(c) The plant will wilt
(d) The plant will continue to grow

Answer: (c) The plant will wilt

Xylem vessels transport water and dissolved minerals upwards; blocking them stops water supply, causing wilting.

Teacher's Note:
a) Xylem transports water while phloem transports synthesized food throughout the plant.
b) Loss of turgidity due to water stress results in drooping or wilting of plant leaves.

12. Which of the following is a false fruit? [1 Mark]
(a) Tomato
(b) Apple
(c) Potato
(d) Pea

Answer: (b) Apple

In an apple, the floral receptacle/base becomes fleshy along with the ovary, classifying it as a false fruit.

Teacher's Note:
a) True fruits develop exclusively from the ovary, whereas false fruits develop with participation of other floral parts.
b) Pear and strawberry are other common examples of false fruits.

13. Amoeba reproduces by________ [1 Mark]
(a) Regeneration
(b) Binary fission
(c) Multiple fission
(d) Fragmentation

Answer: (b) Binary fission

Amoeba reproduces asexually when the parent cell divides into two identical daughter cells through binary fission.

Teacher's Note:
a) Binary fission involves nuclear division followed by cytoplasmic division.
b) Asexual reproduction produces genetically identical offspring from a single parent.

14. A state of mental or emotional strain is termed [1 Mark]
(a) Stress
(b) Adolescence
(c) Puberty
(d) Disease

Answer: (a) Stress

Stress refers to physical, mental, or emotional strain or tension resulting from adverse demanding situations.

Teacher's Note:
a) Managing stress effectively is crucial for maintaining mental and physical well-being during adolescence.
b) Do not confuse psychological stress with biological terms like puberty or adolescence.

15. Cortisone hormone is secreted by the ___________. [1 Mark]
(a) Medulla of the adrenal gland
(b) Cortex of the adrenal gland
(c) Anterior lobe of the pituitary gland
(d) Posterior lobe of the pituitary gland

Answer: (b) Cortex of the adrenal gland

The adrenal cortex synthesizes and secretes vital corticosteroid hormones, including cortisone.

Teacher's Note:
a) The adrenal medulla secretes adrenaline and noradrenaline, whereas the cortex secretes corticosteroids.
b) Learn precise endocrine gland regions and their respective hormonal secretions.

Question 2

(A) Give a scientific word for the following: [5 Marks]

1. The process of the union of two gametes. [1 Mark]

Answer: Fertilisation.

Teacher's Note:
a) Fertilisation results in the formation of a diploid zygote.
b) Ensure correct spelling of biological terms in scientific answers.

2. Protruding part of the throat seen in boys. [1 Mark]

Answer: Adams apple.

Teacher's Note:
a) Adam's apple is the enlargement of the larynx caused by hormonal changes during puberty in males.
b) This is a prominent secondary sexual characteristic in adolescent boys.

3. Type of interaction in which one partner receives advantage while the other is at loss. [1 Mark]

Answer: Parasitism.

Teacher's Note:
a) In parasitism, the parasite benefits while the host is harmed.
b) Contrast this with mutualism where both species benefit.

4. Domesticated animals reared for food or other uses. [1 Mark]

Answer: Livestock.

Teacher's Note:
a) Livestock includes animals like cattle, sheep, goats, and pigs raised for agricultural utility.
b) Proper management of livestock is essential for dairy and meat production.

5. The membranous covering of the heart. [1 Mark]

Answer: Pericardium.

Teacher's Note:
a) The pericardium is a double-layered sac containing fluid that protects the heart from friction and mechanical shock.
b) Memorize protective membranes like pericardium for the heart and meninges for the brain.

(B) Fill in the blanks and rewrite the sentences: [5 Marks]

1. Ferns reproduce asexually by ___________. [1 Mark]

Answer: Ferns reproduce asexually by spore formation.

Teacher's Note:
a) Spores are reproductive cells produced in sporangia on the underside of fern leaves.
b) Always rewrite the complete sentence when answering fill-in-the-blank questions in examinations.

2. ____________ vaccine is given for poliomyelitis. [1 Mark]

Answer: Salk's (or oral polio) vaccine is given for poliomyelitis.

Teacher's Note:
a) Both Salk (IPV) and Sabin (OPV) vaccines are used to prevent polio.
b) Vaccination stimulates the immune system to produce antibodies against specific pathogens.

3. __________ is the seat of intelligence and consciousness. [1 Mark]

Answer: Cerebrum is the seat of intelligence and consciousness.

Teacher's Note:
a) The cerebrum is the largest part of the human brain, controlling higher mental functions.
b) It manages memory, reasoning, voluntary actions, and sensory perception.

4. Phloem chiefly consists of ____________ and companion cells. [1 Mark]

Answer: Phloem chiefly consists of sieve tubes and companion cells.

Teacher's Note:
a) Phloem is responsible for the translocation of organic food materials in plants.
b) Companion cells assist sieve tube elements in metabolic functions.

5. In ____________________ both the interacting species are benefited. [1 Mark]

Answer: In symbiosis (or mutualism) both the interacting species are benefited.

Teacher's Note:
a) Lichens and nitrogen-fixing bacteria in legume root nodules are classic examples of symbiosis.
b) Ecological interactions define how species survive and co-exist in an ecosystem.

Question 3

(A) Match the items in column I with the appropriate items in column II. [5 Marks]

Answer:
1 - c
2 - e
3 - a
4 - b
5 - d

Teacher's Note:
a) Match columns accurately by writing the corresponding pairs clearly.
b) Gir forest is famous for Asiatic lions in Gujarat, while Jim Corbett is India's oldest national park in Uttarakhand.

(B) Study the diagram below and answer the questions that follow: [5 Marks]
[Figure: Diagram of a human brain showing numbered parts: 1 pointing to the cerebrum, 2 pointing to the cerebellum, and 3 pointing to the medulla oblongata.]

1. Label the numbered parts. [3 Marks]

Answer:
1. Cerebrum
2. Cerebellum
3. Medulla oblongata

Teacher's Note:
a) Practice diagrams of the human brain regularly for identification questions.
b) Ensure spellings of neuro-anatomical parts like medulla oblongata are accurate.

2. Write the functions of part 1 and part 3. [2 Marks]

Answer:
Function of Part 1 (Cerebrum): It is the seat of intelligence, consciousness, and willpower. It controls all voluntary activities and interprets sensory impulses.
Function of Part 3 (Medulla oblongata): It controls involuntary actions such as heartbeat, breathing, and peristalsis. Injury to the medulla oblongata results in death.

Teacher's Note:
a) The cerebrum manages higher cognitive functions while the medulla regulates vital autonomic functions.
b) Clearly distinguish between voluntary and involuntary brain control centres.

Question 4

(A) An apparatus shown alongside was set up in sunlight for about an hour. It was observed that drops of water appeared on the inside of the polythene bag. [5 Marks]
[Figure: Potted plant enclosed entirely within a transparent polythene bag tied securely around the base of the stem, set up in sunlight.]

1. Name the process which is being demonstrated. [1 Mark]

Answer: Transpiration.

Teacher's Note:
a) Transpiration is the loss of water in the form of water vapour from the aerial parts of plants.
b) Condensation of transpired water vapour on the inner surface of the polythene bag creates water droplets.

2. Why are the pot and the soil left uncovered by the polythene bag? [1 Mark]

Answer: The pot and soil are left uncovered because the experiment aims to observe water loss exclusively from the plant. Covering the pot would cause evaporation of water from the soil, leading to inaccurate results.

Teacher's Note:
a) Controlling variables is essential for scientific experiments to ensure valid conclusions.
b) Soil evaporation would interfere with the measurement of plant transpiration.

3. Why was the plant left in the sunlight? [1 Mark]

Answer: Sunlight increases the rate of transpiration by raising temperature and opening stomata, making the results clearly observable within a short time.

Teacher's Note:
a) Light intensity is a key environmental factor influencing the rate of transpiration.
b) Higher light intensity stimulates stomatal opening for gas exchange, enhancing water vapor release.

4. Suppose the pot in this experiment, was placed inside a room instead of placing it in the sunlight. What difference would be noticed? [2 Marks]

Answer: If placed inside a room, the rate of transpiration would be significantly lower. As a result, fewer water droplets would condense on the inner side of the polythene bag compared to the setup kept in direct sunlight.

Teacher's Note:
a) Indoor light and lower temperature reduce the transpiration rate.
b) Comparative experimental questions require explaining both cause and expected outcome.

(B) Draw a neat diagram of the following and only label the parts mentioned against it. [5 Marks]

1. Structure of a seed. [2½ Marks]

Answer:
[Figure: Diagram showing a dissected seed showing seed coat, cotyledon, plumule, radicle, and axis.]
Labels required: Seed coat, Cotyledon, Plumule, Radicle, Axis.

Teacher's Note:
a) Ensure diagrams are neat, well-proportioned, and correctly labelled with straight lines.
b) Only the specified labels should be marked to gain full credit.

2. Human sperm. [2½ Marks]

Answer:
[Figure: Diagram of a human spermatozoon showing acrosome, head, neck, midpiece, and tail.]
Labels required: Acrosome, Head, Neck, Midpiece, Tail.

Teacher's Note:
a) Clearly depict structural regions including the head with acrosome and the motile flagellum (tail).
b) Label placement must point precisely to the correct cellular components.

Question 5

(A) Give one point of difference between the following on the basis of what is given in the brackets: [5 Marks]

1. Asexual reproduction and sexual reproduction (gametes) [1 Mark]

Teacher's Note:
a) Always restrict your point of difference strictly to the parameter specified in brackets.
b) Asexual reproduction relies on mitotic division without gametic fusion.

2. Hypogeal germination and epigeal germination (cotyledons) [1 Mark]

Teacher's Note:
a) Hypogeal germination involves rapid elongation of the epicotyl.
b) Epigeal germination involves rapid elongation of the hypocotyl pushing cotyledons upward.

3. Calyx and corolla (function) [1 Mark]

Teacher's Note:
a) Calyx consists of sepals which are usually green.
b) Corolla consists of brightly colored petals adapted for pollination.

4. Fry and fingerlings (definition) [1 Mark]

Teacher's Note:
a) Fry represent the earliest developmental stage after hatching in fish farming.
b) Fingerlings are older, larger juvenile fish ready for stocking in ponds.

5. Red blood cell and white blood cell (structure) [1 Mark]

Teacher's Note:
a) RBC structure maximizes surface area for oxygen transport.
b) WBC structure facilitates amoeboid movement and immune defence.

(B) Choose the odd one out and give the category for the remaining three. [5 Marks]

1. Root, Stem, Leaf, Seed, Fruit [1 Mark]

Answer:
Odd one out: Seed.
Category for remaining three: Vegetative parts of a plant (or parts used for vegetative propagation / parts of a plant).

Teacher's Note:
a) Roots, stems, and leaves are vegetative organs, whereas seeds are reproductive structures.
b) State both the odd item and the exact common category clearly to earn full marks.

2. Thyroid stimulating hormone, Growth hormone, Adrenocorticotropic hormone, Adrenaline, Anti-diuretic hormone [1 Mark]

Answer:
Odd one out: Adrenaline.
Category for remaining three: Hormones secreted by the pituitary gland .

Teacher's Note:
a) Adrenaline is secreted by the adrenal medulla, while the others are pituitary hormones.
b) Carefully analyze endocrine glands and their respective secretions.

3. Nitrogen, Phosphorus, Potassium, Iron [1 Mark]

Answer:
Odd one out: Iron.
Category for remaining three: Macronutrients required by plants.

Teacher's Note:
a) Nitrogen, phosphorus, and potassium are primary macronutrients (NPK fertilizers).
b) Iron is classified as a micronutrient required in trace amounts.

4. Pomphret, Tilapia, Bombay duck, Snapper, Mackerel [1 Mark]

Answer:
Odd one out: Tilapia.
Category for remaining three: Marine water fish.

Teacher's Note:
a) Tilapia is a freshwater fish, whereas pomphret, Bombay duck, snapper, and mackerel are marine fish.
b) Differentiate correctly between marine and freshwater aquatic species.

5. Stigma, Style, Embryo sac, Anther, Egg [1 Mark]

Answer:
Odd one out: Anther.
Category for remaining three: Parts of the female reproductive system (pistil/carpel) of the flower.

Teacher's Note:
a) Anther is part of the stamen (male reproductive organ), while stigma, style, embryo sac, and egg belong to the pistil.
b) Master floral anatomy to distinguish male and female reproductive whorls.

Question 6

(A) Complete the following and rewrite the table. [5 Marks]

Answer:
1. Pancreas
2. Regulates blood glucose level
3. Hypoglycemia
4. Thyroxine
5. Simple goitre
6. Exophthalmic goitre
7. Pituitary gland
8. Growth hormone
9. Dwarfism
10. Gigantism

Teacher's Note:
a) Memorize major endocrine glands, their hormones, functions, and deficiency/excess disorders.
b) Hyposecretion means underproduction while hypersecretion means overproduction of hormones.

(B) Define the following terms: [5 Marks]

1. Blood pressure [1 Mark]

Answer: Blood pressure is the pressure which the flowing blood exerts on the walls of the arteries.

Teacher's Note:
a) Blood pressure is measured in millimeters of mercury (mmHg) using a sphygmomanometer.
b) Systolic and diastolic pressures represent contraction and relaxation phases of the heart.

2. Disease [1 Mark]

Answer: Disease is an abnormal condition that impairs the normal functioning of the body.

Teacher's Note:
a) Diseases can be classified as infectious (communicable) or non-infectious (non-communicable).
b) Maintaining personal hygiene helps prevent many common diseases.

3. Semi-permeable membrane [1 Mark]

Answer: A semi-permeable membrane is a membrane which allows only selective materials to pass through it.

Teacher's Note:
a) Cell membranes act as biological semi-permeable membranes during osmosis.
b) Solvent molecules pass freely while solute particles are restricted.

4. Sericulture [1 Mark]

Answer: Sericulture is the artificial rearing of silkworms to obtain raw silk.

Teacher's Note:
a) Silkworms (Bombyx mori) are fed on mulberry leaves in sericulture farms.
b) Silk cocoons are processed to extract natural silk fibers.

5. Food web [1 Mark]

Answer: Several interconnected food chains together constitute a food web.

Teacher's Note:
a) Food webs reflect real ecological feeding relationships rather than linear food chains.
b) They provide greater ecological stability to ecosystems.

Question 7

(A)

1. Given below is a diagram of a method of transportation in plants. Identify and explain the method in brief. [3 Marks]
[Figure: Diagram showing mineral ions moving from a region of high concentration outside in the soil to a region of low concentration inside the root hair cell across the cell membrane.]

Answer:
Identification: Diffusion.
Explanation: Diffusion is the free movement of molecules of a substance from a region of its higher concentration to a region of its lower concentration until the concentration in both regions is equal. If the concentration of mineral ions outside the cell is higher than the cytoplasm of the root hair cell, mineral salts enter the cell by diffusion.

Teacher's Note:
a) Diffusion is a passive transport mechanism requiring no cellular energy expenditure.
b) It plays a key role in the uptake of mineral ions and gases in plants.

2. Which endocrine gland is called master gland? Why? [2 Marks]

Answer: The pituitary gland is called the master gland. It secretes several hormones, some of which regulate the activity of other endocrine glands.

Teacher's Note:
a) The pituitary gland is located at the base of the brain attached to the hypothalamus.
b) Its tropic hormones control the functioning of thyroid, adrenal, and gonadal glands.

(B)

1. State any three symptoms of protein deficiency kwashiorkor. [2 Marks]

Answer:
1. The child has dull skin and hair.
2. The child shows oedema, i.e., swelling on the skin due to water retention.
3. Retarded physical and mental growth in children.

Teacher's Note:
a) Kwashiorkor is a severe protein deficiency disease common in toddlers in developing regions.
b) Providing balanced diets rich in proteins prevents deficiency disorders like kwashiorkor and marasmus.

2. Explain the process of blood clotting. [3 Marks]

Answer:
1. Platelets disintegrate at the site of injury and release an enzyme (thromboplastin).
2. This enzyme converts soluble fibrinogen present in blood plasma into insoluble fibrin.
3. Fibrin forms a fine mesh in which RBCs get trapped, contracting to form a clot and stopping bleeding.

Teacher's Note:
a) Blood clotting (coagulation) is a protective mechanism preventing excessive blood loss.
b) Vitamin K and calcium ions play vital roles in the blood clotting cascade.