ICSE Class 10 Biology Board Exam Question Paper 2017 with Solutions

ICSE Class 10 Biology Board Exam Question Paper 2017 with Solutions

Section -1 [40 Marks]

(Attempt All questions from this section)

Question 1.

(a) Name the following: [5 Marks]
(i) The process by which root hairs absorb water from the soil.
(ii) The organ which produces urea.
(iii) The kind of lens required to correct Myopia.
(iv) The pituitary hormone which stimulates contraction of uterus during child birth.
(v) The international health organisation which educates people in accident prevention.

Answer:
(i) Osmosis
(ii) Liver
(iii) Concave lens
(iv) Oxytocin
(v) Red Cross

Teacher's Note:
a) This question tests fundamental biological terms and concepts across various chapters like plant physiology, human anatomy, and health organizations.
b) Students should pay attention to precise terminology, especially for medical conditions and hormones, as similar-sounding terms can have different meanings.

(b) Choose the correct answer from each of the four options given below: [5 Marks]
(i) The prime source of chlorofluorocarbons is :
A. Vehicular emissions
B. Industrial effluents
C. Domestic sewage
D. Refrigeration equipments

Answer: (D) Refrigeration equipments

Teacher's Note:
a) Chlorofluorocarbons (CFCs) are primarily used as refrigerants, propellants in aerosol sprays, and in foam blowing, making refrigeration equipment a major source.
b) CFCs are known for their role in ozone layer depletion, a critical environmental concern.

(ii) Penicillin obtained from a fungus is :
A. Antibiotic
B. Antiseptic
C. Antibody
D. Antiserum

Answer: (A) Antibiotic

Teacher's Note:
a) Penicillin was the first antibiotic discovered by Alexander Fleming, derived from the fungus Penicillium notatum.
b) Antibiotics are substances that kill or inhibit the growth of microorganisms, particularly bacteria, and are crucial in treating bacterial infections.

(iii) Marine fish when placed in tap water bursts because of:
A. Endosmosis
B. Exosmosis
C. Diffusion
D. Plasmolysis

Answer: (A) Endosmosis

Teacher's Note:
a) Marine fish have body fluids that are hypertonic to tap water. When placed in tap water, water moves into the fish's cells by endosmosis, causing them to swell and burst.
b) This illustrates the principle of osmosis, where water moves from a region of higher water potential (lower solute concentration) to a region of lower water potential (higher solute concentration) across a semi-permeable membrane.

(iv) Surgical method of sterilization in a woman involves cutting and tying of:
A. Ureter
B. Uterus
C. Urethra
D. Oviduct

Answer: (D) Oviduct

Teacher's Note:
a) The surgical sterilization method in females is called tubectomy, which involves cutting and tying the fallopian tubes (oviducts) to prevent the egg from reaching the uterus and sperm from reaching the egg.
b) This procedure effectively prevents fertilization and thus pregnancy.

(v) Synthesis phase in the cell cycle is called so, because of the synthesis of more:
A. RNA
B. RNA and proteins
C. DNA
D. Glucose

Answer: (C) DNA

Teacher's Note:
a) The S-phase (Synthesis phase) of the cell cycle is characterized by the replication of DNA, where the amount of DNA doubles, ensuring that each daughter cell receives a complete set of chromosomes.
b) While RNA and proteins are also synthesized during other phases (G1 and G2), DNA synthesis is the defining event of the S-phase.

(c) The statements given below are incorrect. Rewrite the correct statement by changing the underlined words of the statements. [5 Marks]
(i) The Graafian follicle, after ovulation turns into a hormone producing tissue called Corpus callosum.
(ii) Deafness is caused due to the rupturing of the Pinna.
(iii) Gyri and Sulci are the folds of Cerebellum.
(iv) Free movement of solutes in and out of the cell takes place across the cell membrane.
(v) The solvent used to dissolve the chlorophyll pigments while testing a leaf for starch is Soda lime.

Answer:
(i) The Graafian follicle, after ovulation turns into a hormone producing tissue called Corpus luteum.
(ii) Deafness is caused due to rupturing of the eardrum/tympanum.
(iii) Gyri and Sulci are the folds of Cerebrum.
(iv) Free movement of solute in and out of the cell takes place across the cell wall.
(v) The solvent used to dissolve the chlorophyll pigments while testing a leaf for starch is Methylated spirit / Alcohol.

Teacher's Note:
a) This question assesses the student's knowledge of specific biological terms and their correct application in various contexts.
b) It is important to understand the precise function and location of structures (e.g., Corpus luteum vs. Corpus callosum, eardrum vs. pinna) and the properties of different cell components (e.g., cell membrane vs. cell wall) to identify and correct the errors.

(d) Given below are sets of five terms each. Rewrite the terms in correct order in a logical sequence. [5 Marks]
Example : Large intestine, Stomach, Mouth, Small intestine, Oesophagus.
Answer : Mouth → Oesophagus → Stomach → Small intestine → Large intestine.

(i) Fibrin, Platelets, Thromboplastin, Fibrinogen, Thrombin.
(ii) Cochlea, Malleus, Pinna, Stapes, Incus.
(iii) Receptor, Spinal cord, Effector, Motor neuron, Sensory neuron.
(iv) Uterus, Parturition, Fertilisation, Gestation, Implantation.
(v) Caterpillar, Snake, Owl, Frog, Green leaves.

Answer:
(i) Platelets → Thromboplastin → Thrombin → Fibrinogen → Fibrin.
(ii) Pinna → Malleus → Incus → Stapes → Cochlea.
(iii) Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector.
(iv) Fertilisation → Implantation → Gestation → Parturition.
(v) Green leaves → Caterpillar → Frog → Snake → Owl.

Teacher's Note:
a) This question requires students to understand the sequence of events or structures in various biological processes, such as blood clotting, sound transmission, reflex arc, reproduction, and food chains.
b) For sequences involving organs or structures, tracing the path of a substance or signal is often helpful. For processes, identifying the chronological order of steps is key.

(e) Choose the ODD one out of the following terms given and name the CATEGORY to which the others belong : [5 Marks]
(i) Aqueous humour, Vitreous humour, Iris, Central canal
(ii) Formalin, Iodine, DDT, Lime
(iii) ACTH, TSH, ADH, FSH
(iv) Phosphate, RNA, Sugar, Nitrogenous base
(v) Bile, Urea, Uric acid, Ammonia

Answer:
(i) Central canal
Rest are concerned with eyes
(ii) DDT
Rest are antiseptics/disinfectants
(iii) ADH
Rest are hormones of anterior pituitary
(iv) RNA
Rest are components of DNA
(v) Bile
Rest are excretory products of humans

Teacher's Note:
a) This question tests the ability to classify biological terms and identify the one that does not fit a specific category, along with naming that category.
b) For Q1(e)(ii), the official key states Iodine as the odd one out and "Rest are disinfectants". However, DDT is a pesticide, not a disinfectant. Formalin, Iodine, and Lime are all used for killing microbes (disinfectants/antiseptics). Therefore, DDT is the correct odd one out, and the category for the others is antiseptics/disinfectants.

(f) Given below are groups of terms. In each group the first pair indicates the relationship between the two terms. Rewrite and complete the second pair on a similar basis. [5 Marks]
Example: Oxygen: Inspiration:: Carbon dioxide: Expiration

(i) Eye: Optic nerve:: Ear :
(ii) Cytoplasm : Cytokinesis:: Nucleus :
(iii) TT: Homozygous:: Tt:
(iv) Foetus: Amnion:: Heart:
(v) Adenine: Thymine:: Cytosine :

Answer:
(i) Eye: Optic nerve:: Ear: Auditory nerve
(ii) Cytoplasm : Cytokinesis:: Nucleus: Karyokinesis
(iii) TT: Homozygous:: Tt: Heterozygous
(iv) Foetus: Amnion:: Heart: Pericardium
(v) Adenine: Thymine:: Cytosine: Guanine

Teacher's Note:
a) This question requires identifying analogies and relationships between biological terms, covering topics from sensory organs to genetics and cell division.
b) Students should carefully analyze the relationship in the first pair (e.g., organ to nerve, part to process, genotype to condition) and apply the same logic to complete the second pair.

(g) Match the items given in Column A with the most appropriate ones in Column B and rewrite the correct matching pairs.

Answer:

Teacher's Note:
a) This matching exercise tests knowledge across various biological domains, including human physiology (ear, diseases), genetics, and environmental regulations.
b) Students should carefully consider the definition or association of each term in Column A to find its most accurate match in Column B, eliminating distractors.

(h) The diagram given below represents the location and structure of an endocrine gland. Study the same and answer the questions that follow: [5 Marks]

[Figure: Diagram showing the thyroid gland located in the neck, anterior to the trachea, with two lobes connected by an isthmus.]

(i) Name the endocrine gland shown in the diagram.
(ii) Name the hormone secreted by this gland.
(iii) Which mineral is essential for the synthesis of this hormone?
(iv) Name the condition caused due to undersecretion of this hormone in children.
(v) Name the condition caused due to oversecretion of this hormone in adults.

Answer:
(i) Thyroid gland
(ii) Thyroxine
(iii) Iodine
(iv) Cretinism
(v) Exophthalmic goitre / Grave's disease

Teacher's Note:
a) This question focuses on the thyroid gland, its hormone, essential mineral for synthesis, and associated disorders due to hypo- or hypersecretion.
b) Students should remember the specific names of hormones and the conditions caused by their imbalance, distinguishing between effects in children and adults.

Section – II [40 Marks]

(Attempt any four questions from this Section)

Question 2.

(a) Study the diagram given below which represents a stage during the mitotic cell division and answer the questions that follow: [5 Marks]

[Figure: Diagram showing a cell undergoing division, with two distinct groups of decondensing chromosomes at opposite poles, and a forming nuclear envelope around each group. Spindle fibers are disappearing. A constriction is visible in the middle, indicating cytokinesis is also in progress. Label 1 points to a centromere, Label 2 points to the forming nuclear membrane.]

(i) Identify the stage giving suitable reasons.
(ii) Name the parts numbered 1 and 2.
(iii) What is the technical term for the division of nucleus?
(iv) Mention the stage that comes before the stage shown in the diagram. Draw a neat labelled diagram of the stage mentioned.
(v) Which is the cell division that results in half the number of chromosomes in daughter cells?

Answer:
(i) The stage is Telophase. The reason is that the nucleus and nucleolus reappear, and spindle fibres disappear. The chromosomes decondense at opposite poles, and a nuclear envelope forms around each set.

(ii)
1. Centromere
2. Nuclear membrane/Nucleus

(iii) Karyokinesis

(iv) The stage that comes before Telophase is Anaphase.

[Figure: Diagram to be added showing Anaphase. Sister chromatids have separated and are moving towards opposite poles of the cell, pulled by spindle fibers. The centromeres lead the way, and the chromatids appear V-shaped or J-shaped.]

(v) Meiosis

Teacher's Note:
a) This question tests the understanding of different stages of mitosis, their characteristic features, and related terminology.
b) For identifying stages, focus on key events like chromosome movement, nuclear envelope formation/disappearance, and spindle fiber activity. For drawing, ensure all relevant parts are clearly labelled.

(b) Differentiate between the following pairs on the basis of what is mentioned in brackets: [5 Marks]
(i) Active Transport and Diffusion [Significance in plants]
(ii) Demography and Population density [Definition]
(iii) Antibiotic and Antibody [Source]
(iv) Renal cortex and Renal medulla [Parts of the nephrons present]
(v) NADP and ATP [Expand the abbreviation]

Answer:

Teacher's Note:
a) Differentiation questions require clear, concise points of distinction based on the specified criteria, often presented best in a tabular format.
b) Ensure that the points of difference directly address the bracketed instruction and are accurate for both terms being compared.

Question 3.

(a) The diagram given below represents a plant cell after being placed in a strong sugar solution. Study the diagram and answer the questions that follow: [5 Marks]

[Figure: Diagram of a plant cell. The cell wall (1) is intact, but the protoplast (including cell membrane (3), nucleus (4), and cytoplasm) has shrunk and pulled away from the cell wall. The space between the cell wall and the shrunken protoplast is filled with the external strong sugar solution (2).]

(i) What is the state of the cell shown in the diagram?
(ii) Name the structure that acts as a selectively permeable membrane.
(iii) Label the parts numbered 1 to 4 in the diagram.
(iv) How can the above cell be brought back to its original condition? Mention the scientific term for the recovery of the cell.
(v) State any two features of the above plant cell which is not present in animal cells.

Answer:
(i) The state of the cell is Plasmolysed.

(ii) Cell membrane.

(iii)
1. Cell wall
2. Strong sugar solution
3. Cell membrane
4. Nucleus

(iv) By putting it in hypotonic solution/water.
The scientific term for the recovery of the cell is deplasmolysis.

(v)
(i) Cell wall
(ii) Vacuole

Teacher's Note:
a) This question assesses understanding of osmosis in plant cells, specifically plasmolysis and deplasmolysis, and the structural differences between plant and animal cells.
b) Students should clearly distinguish between the cell wall (fully permeable) and the cell membrane (selectively permeable) and understand their roles in water movement.

(b) Given below is a representation of a kind of pollution. Study the same and answer the questions that follow : [5 Marks]

[Figure: A stylized drawing of a loud speaker or a horn emitting sound waves, indicating noise pollution.]

(i) Name the kind of pollution.
(ii) List any three common sources of this pollution.
(iii) Mention three harmful effects of this pollution on human health.
(iv) Explain the term 'Pollutant'.
(v) Name two soil pollutants.

Answer:
(i) Noise pollution.

(ii) Automobiles and road transport, jet aeroplanes, loudspeakers, radio and musical instruments.

(iii) Nervous irritability, damage of eardrum, disturbs peace of mind.

(iv) The agents that cause pollution are called Pollutants.

(v) Pesticides, Styrofoam, Chemical fertilizers, domestic and industrial wastes.

Teacher's Note:
a) This question covers environmental science, focusing on noise pollution, its sources, effects, and the general definition of a pollutant.
b) When listing sources and effects, provide distinct and specific examples. For the definition of a pollutant, emphasize its role in causing undesirable changes in the environment.

Question 4.

(a) The diagrams given below represent the relationship between a mouse and a physiological process that occurs in green plants. Study the diagrams and answer the questions that follow: [5 Marks]

[Figure: Four bell jar setups (A, B, C, D) under sunlight.
A: Bell jar with a mouse and a green plant.
B: Bell jar with a mouse and a burning candle. Mouse is dead.
C: Bell jar with a green plant.
D: Bell jar with a mouse and a green plant. Mouse is alive.
Sunlight is shown falling on setups A, C, D.]

(i) Name the physiological process occurring, in the green plant that has kept the mouse alive.
(ii) Explain the physiological process mentioned above.
(iii) Why did the mouse die in bell jar B?
(iv) What is the significance of the process as stated in (i) for life on earth?
(v) Represent the above mentioned physiological process in the form of a chemical equation.

Answer:
(i) Photosynthesis.

(ii) Photosynthesis is the process by which green plants, in the presence of sunlight and chlorophyll, prepare food in the form of carbohydrates using carbon dioxide and water, releasing oxygen as a byproduct.

(iii) The mouse died in bell jar B because there was no green plant to produce oxygen, and the oxygen present in the bell jar was utilized by the burning candle and the mouse's respiration, leading to oxygen depletion.

(iv) Photosynthesis provides food for almost all life forms on Earth and balances the oxygen and carbon cycle in the atmosphere, maintaining breathable air.

(v)
\( 6CO_2 + 12H_2O \xrightarrow{\text{Chlorophyll, Sunlight}} C_6H_{12}O_6 + 6O_2 + 6H_2O \)

Teacher's Note:
a) This question tests the understanding of photosynthesis, its requirements, products, and ecological significance, as demonstrated through an experimental setup.
b) For the chemical equation, ensure correct reactants, products, and conditions (chlorophyll, sunlight) are included. Be careful with the chemical formula for glucose (C₆H₁₂O₆).

(b) Mention the exact location of the following: [5 Marks]
(i) Prostate gland
(ii) Myelin sheath
(iii) Islets of Langerhans
(iv) Semi-circular canals
(v) Eustachian tube.

Answer:
(i) Inferior to the urinary bladder, encircling the urethra.
(ii) Inner sheath around the axon of a neuron.
(iii) In the pancreas.
(iv) Internal ear, above the utriculus.
(v) Between the middle ear and the pharynx.

Teacher's Note:
a) This question requires precise anatomical knowledge of various structures in the human body.
b) For locations, avoid vague descriptions; instead, specify the exact organ, tissue, or relative position to other structures.

Question 5.

(a) The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the question that follow : [5 Marks]

[Figure: Longitudinal section of a human testis. Label 1 points to the outer covering (scrotum). Label 2 points to the tube leading away from the testis (vas deferens/sperm duct). Label 3 points to the highly coiled structure on the posterior side of the testis (epididymis).]

(i) Label the parts numbered 1 to 3 in the diagram.
(ii) In which part of the testis are the sperms produced?
(iii) State the functions of the parts labelled 1 and 3 in the diagram.
(iv) Name the cells that secrete Testosterone.
(v) Draw a neat, labelled diagram of a sperm.

Answer:
(i)
1. Scrotum
2. Sperm duct/vasa deferens
3. Epididymis

(ii) Sperms are produced in the seminiferous tubules.

(iii)
Scrotum: It provides a temperature 2-3 °C lower than the body temperature, which is optimal for spermatogenesis (maturation of sperms).
Epididymis: It stores sperms and helps in their maturation and acquisition of motility.

(iv) Leydig's cells (or Interstitial cells).

(v)

[Figure: Diagram to be added showing a human sperm with the following labelled parts: Head (containing Acrosome and Nucleus), Middle piece (containing Mitochondria), and Tail (containing Axial filament).]

Teacher's Note:
a) This question covers the male reproductive system, focusing on the structure of the testis, sperm production, and associated hormones.
b) When drawing diagrams, ensure all key parts are accurately represented and clearly labelled. For functions, be specific about the role of each structure.

(b) Give biological reasons for the following statements: [5 Marks]
(i) Some women have facial hair like beard and moustache.
(ii) Cutting of trees should be discouraged.
(iii) In some xerophytes leaves are modified into spines.
(iv) There is frequent urination in winter than in summer.
(v) The left ventricle of the heart has a thicker wall than the right ventricle.

Answer:
(i) Some women have facial hair like a beard and moustache because of adrenal virilism, a condition where there is excess secretion of adrenal androgens (male hormones) from the adrenal cortex, leading to the development of male secondary sexual characteristics in females.

(ii) Cutting of trees should be discouraged because it leads to deforestation, which reduces the amount of carbon dioxide utilized during photosynthesis. This results in an increase in atmospheric CO₂, contributing to the greenhouse effect and global warming.

(iii) Since xerophytes grow in dry conditions where water is scarce, their leaves are modified into spines to reduce the surface area for transpiration, thereby minimizing water loss from the plant.

(iv) In winter, the environmental temperature is low, which reduces sweating (perspiration) from the body. To maintain water balance, the excess water that would normally be lost through sweat is eliminated from the body in the form of urine, leading to more frequent urination.

(v) The left ventricle of the heart has a thicker muscular wall than the right ventricle because it has to pump oxygenated blood with greater force to the remotest parts of the entire systemic circulation of the body, whereas the right ventricle only pumps blood to the lungs.

Teacher's Note:
a) This section requires providing scientific explanations for various biological phenomena, demonstrating an understanding of underlying physiological processes.
b) Ensure that the reasons are biologically accurate, complete, and directly address the statement provided, using appropriate terminology.

Question 6.

(a) The diagram given below represents a section of the human heart. Answer the questions that follow: [5 Marks]

[Figure: Diagram showing a section of the human heart. Label 1 points to the pulmonary artery originating from the right ventricle. Label 2 points to the pulmonary veins entering the left atrium.]

(i) Which parts of heart are in the diastolic phase? Give a reason to support your answer.
(ii) Label the parts numbered 1 and 2 in the diagram. What type of blood flows through them?
(iii) What causes the heart sounds ‘LUBB' and 'DUP'?
(iv) Name the blood vessels that supply oxygenated blood to the heart muscles.
(v) Draw neat labelled diagrams of a cross-section of an artery and a vein.

Answer:
(i) The ventricles are in the diastolic phase. This is because during ventricular diastole, the tricuspid and bicuspid (mitral) valves are open, allowing blood to flow from the atria into the ventricles for filling.

(ii)
1. Pulmonary artery (carries deoxygenated blood)
2. Left pulmonary veins (carry oxygenated blood)

(iii) The 'LUBB' sound is caused by the closure of the auriculo-ventricular valves (tricuspid and bicuspid) at the beginning of ventricular systole. The 'DUP' sound is caused by the closure of the semilunar valves (aortic and pulmonary) at the beginning of ventricular diastole.

(iv) Coronary arteries supply oxygenated blood to the heart muscles.

(v)

[Figure: Diagram to be added showing a cross-section of an artery and a vein.
Artery: Thick, muscular wall (Tunica media), narrow lumen, distinct layers (Tunica externa, Tunica media, Tunica interna).
Vein: Thinner wall, wider and often irregular lumen, less muscular Tunica media, presence of valves (optional in diagram but characteristic). Labels for External layer (Tunica externa), Middle layer (Tunica media), Inner layer (Tunica interna), and Lumen should be present for both.]

Teacher's Note:
a) This question covers the structure and function of the human heart, including the cardiac cycle, blood vessels, and heart sounds.
b) For labelling, ensure accuracy. For heart sounds, remember which valves close at which stage. For diagrams of blood vessels, highlight the key structural differences like wall thickness and lumen size.

(b) Give appropriate biological/technical terms for the following: [5 Marks]
1. The type of immunity that exists in our body due to our genetic makeup.
2. The suppressed allele of a gene.
3. The accessory gland in human males whose secretion activates the sperms.
4. An apparatus that measures the rate of water uptake in a cut shoot due to transpiration.
5. The kind of twins formed from two fertilised eggs.
6. A pair of corresponding chromosomes of the same size and shape, one from each parent.
7. The mild chemical substance which when applied on the body kills germs.
8. The type of waste generated in hospitals and pathological laboratories.
9. The antiseptic substance in tears.
10. Cellular components of blood containing haemoglobin.

Answer:
1. Innate/Inborn immunity
2. Recessive
3. Seminal vesicles
4. Ganong's potometer
5. Non-identical/Fraternal twins
6. Homologous chromosome
7. Antiseptic
8. Biomedical Wastes
9. Lysozymes
10. Red blood cells / Red blood corpuscles

Teacher's Note:
a) This question tests a broad range of biological vocabulary, covering genetics, human physiology, plant physiology, and health.
b) Students should be familiar with precise technical terms for various biological concepts. For Q6(b)6, ensure the spelling is "chromosome" not "chromostone".

Question 7.

(a) In a homozygous pea plant, axial flowers (A) are dominant over terminal flowers (a). [5 Marks]
(i) What is the phenotype and genotype of the F₁ generation if a plant bearing pure axial flowers is crossed with a plant bearing pure terminal flowers?
(ii) Draw a Punnett square board to show the gametes and offsprings when both the parent plants are heterozygous for axial flowers.
(iii) What is the phenotypic ratio and genotypic ratio of the above cross shown in (ii)?
(iv) State Mendel's Law of Dominance.
(v) Name two genetic disorders commonly seen in human males.

Answer:
(i) If a pure axial flowered plant (AA) is crossed with a pure terminal flowered plant (aa):
Parents: AA (Pure Axial) x aa (Pure Terminal)
Gametes: A, A x a, a
F₁ generation: All Aa
Phenotype of F₁ generation: All plants will have axial flowers.
Genotype of F₁ generation: All plants will be Aa.

(ii) Punnett square for a cross between two heterozygous plants (Aa x Aa):

(iii) From the Punnett square in (ii):
Phenotypic ratio: 3 Axial : 1 Terminal
Genotypic ratio: 1 AA : 2 Aa : 1 aa (or 1:2:1)

(iv) Mendel's Law of Dominance states that in a cross between two pure parents differing in one pair of contrasting characters, only one character (the dominant one) expresses itself in the F₁ generation, while the other character (the recessive one) remains unexpressed. The allele that expresses itself phenotypically is called dominant, and the one that remains unexpressed is called recessive.

(v) Two genetic disorders commonly seen in human males are Colourblindness and Haemophilia.

Teacher's Note:
a) This question tests fundamental principles of Mendelian genetics, including monohybrid crosses, Punnett squares, phenotypic and genotypic ratios, and the Law of Dominance.
b) When solving genetics problems, clearly state the genotypes of parents, gametes, and offspring. For Punnett squares, ensure all possible combinations are shown. Remember that X-linked recessive disorders are more common in males.

(b) The diagram given below is an external view of the human brain. Study the same and answer the questions that follow : [5 Marks]

[Figure: External view of the human brain. Label A points to the cerebrum (the large, convoluted anterior part). Label B points to the cerebellum (the smaller, convoluted part located posterior and inferior to the cerebrum). Label C points to the brainstem/spinal cord extending downwards from the brain.]

(i) Name the parts labelled A, B and C in the diagram.
(ii) What are the structural and functional units of the brain? How are the parts of these units arranged in A and C?
(iii) Mention the collective term for the membranes covering the brain.
(iv) What is the function of Cerebrospinal fluid?

Answer:
(i)
A. Cerebrum
B. Cerebellum
C. Spinal cord

(ii) The structural and functional units of the brain are Neurons/Nerve cells.
In A (Cerebrum), the grey matter (containing cell bodies of neurons) is located outside (cerebral cortex), and the white matter (containing myelinated axons) is inside.
In C (Spinal cord), the grey matter is located inside (H-shaped central region), and the white matter is outside.

(iii) Meninges.

(iv) The Cerebrospinal fluid (CSF) serves as a shock-absorbing medium, protecting the brain and the rest of the Central Nervous System (CNS) against mechanical shocks, jerks, and jolts. It also helps in maintaining a constant pressure in and around the brain and provides nutrients while removing waste products.

Teacher's Note:
a) This question focuses on the anatomy of the human brain, its major parts, their functions, and associated protective structures.
b) Students should know the specific functions of the cerebrum and cerebellum, the arrangement of grey and white matter in the brain and spinal cord, and the protective roles of meninges and CSF.