ICSE Class 10 Biology Sample Paper 2024 with Solutions

SECTION A

Question 1

Choose the correct answers to the questions from the given options. [15]
(i) Loss of water as droplets from the hydathodes is called: [1 Mark]
(a) Transpiration
(b) Bleeding
(c) Guttation
(d) Evaporation

Answer: (c) Guttation

Guttation is the exudation of drops of xylem sap from the leaves or edges of plants.

Teacher's Note:
a) Guttation occurs through specialized structures called hydathodes, usually seen under high root pressure and high humidity.
b) Do not confuse guttation with transpiration, which involves the loss of water in the form of vapor through stomata.

(ii) Synthesis phase in the cell cycle is called so, because of the synthesis of more: [1 Mark]
(a) Glucose
(b) Proteins
(c) RNA
(d) DNA

Answer: (d) DNA

The Synthesis (S) phase is characterized by the replication of DNA.

Teacher's Note:
a) During the S phase, the amount of DNA per cell doubles while the chromosome number remains the same.
b) Students often incorrectly choose RNA or proteins, which are synthesized throughout interphase but primarily in G1 and G2 phases.

(iii) While playing with his friends, Peter inserted a stick into his ear. He lost his hearing due to the rupture of: [1 Mark]
(a) Ear drum
(b) Pericardium
(c) Cornea
(d) Pinna

Answer: (a) Ear drum

The tympanic membrane or ear drum separates the external ear from the middle ear and vibrates when sound waves hit it.

Teacher's Note:
a) Insertion of foreign objects can easily puncture the delicate tympanic membrane, leading to conductive hearing loss.
b) Ensure students know the scientific name (tympanic membrane) as well as the common name (ear drum).

(iv) The prime source of Chloro fluorocarbons is: [1 Mark]
(a) Vehicular emissions
(b) Refrigeration equipment
(c) Sewage
(d) Effluents

Answer: (b) Refrigeration equipment

Chlorofluorocarbons (CFCs) are widely used as refrigerants and propellants in aerosol cans.

Teacher's Note:
a) CFCs are major ozone-depleting substances released primarily from cooling and refrigeration systems.
b) Vehicular emissions mainly contribute to carbon monoxide, nitrogen oxides, and unburnt hydrocarbons.

(v) Oxygenated blood to heart is supplied by: [1 Mark]
(a) Hepatic artery
(b) Coronary artery
(c) Renal artery
(d) Pulmonary artery

Answer: (b) Coronary artery

The coronary arteries branch off from the aorta and supply oxygenated blood directly to the heart muscle.

Teacher's Note:
a) The heart muscle itself requires a continuous supply of oxygen and nutrients to function effectively.
b) Do not confuse coronary artery with pulmonary artery, which carries deoxygenated blood from the heart to the lungs.

(vi) Assertion (A): There is frequent urination in summer than in winter.
Reason (R): In summer we lose a lot of water as sweat, so the kidneys reabsorb more water. Hence, urine formed is less in summer than in winter. [1 Mark]
(a) Both A and R are True
(b) Both A and R are False
(c) A is True and R is False
(d) A is False and R is True

Answer: (d) A is False and R is True

There is less frequent urination in summer because water is lost through sweat, leading to concentrated urine, making Assertion false while Reason is scientifically correct.

Teacher's Note:
a) In winter, due to the absence of sweating, more water is eliminated through urine, causing frequent urination.
b) Read both Assertion and Reason carefully to analyze the causal relationship before choosing the option.

(vii) The age restrictions for marriage for boys and girls by law in India is: [1 Mark]
(a) Boys 18 years, Girls 21 years
(b) Boys 17 years, Girls 16 years
(c) Boys 21 years, Girls 18 years
(d) Boys 20 years, Girls 17 years

Answer: (c) Boys 21 years, Girls 18 years

The legal age of marriage under Indian law is 21 years for males and 18 years for females.

Teacher's Note:
a) These age limits are established to ensure physical and mental maturity before entering parenthood.
b) Pay close attention to the order of boys and girls in the options to avoid silly mistakes.

(viii) Hari is fond of watching the fish in an aquarium. So, he set up an aquarium in his house. Along with a number of fresh water fish, he also placed a clown fish which is a salt water fish. After few hours, the clown fish was found dead and floating on water. This was due to: [1 Mark]
(a) Endosmosis
(b) Exosmosis
(c) Osmoregulation
(d) Excretion

Answer: (a) Endosmosis

A saltwater fish placed in fresh water experiences endosmosis due to the hypotonic surrounding, causing its cells to swell and burst.

Teacher's Note:
a) Endosmosis is the inward movement of water into a cell when placed in a hypotonic solution.
b) Conversely, freshwater fish placed in saltwater would experience exosmosis and shrink.

(ix) The solvent used for dissolving chlorophyll while testing a leaf for starch is: [1 Mark]
(a) Sodium hydroxide
(b) Lime water
(c) Water
(d) Ethyl alcohol

Answer: (d) Ethyl alcohol

Warm methylated spirit or ethyl alcohol is used in a water bath to decolorize the leaf by dissolving chlorophyll.

Teacher's Note:
a) Alcohol dissolves chlorophyll effectively making the subsequent iodine test clearly visible.
b) Direct heating over a flame must be avoided as alcohol is highly flammable; it is always heated in a water bath.

(x) The structure related to storage and maturation of sperms in a human male is: [1 Mark]
(a) Epididymis
(b) Epidermis
(c) Epithelium
(d) Endothelium

Answer: (a) Epididymis

The epididymis is a coiled tube located on the outer surface of each testis where sperms are temporarily stored and undergo functional maturation.

Teacher's Note:
a) Epididymis provides the appropriate physiological environment for sperms to acquire motility.
b) Do not confuse epididymis with epidermis, which is an outer layer of tissue.

(xi) A sequence of DNA has 200 nitrogenous base pairs, of which 100 are Thymine-Adenine pairs. What is the number of Cytosine-Guanine pairs in this sequence: [1 Mark]
(a) 50
(b) 200
(c) 100
(d) 25

Answer: (c) 100

Total base pairs = 200. If 100 are Thymine-Adenine pairs, the remaining 100 must be Cytosine-Guanine pairs.

Teacher's Note:
a) According to Chargaff's rules, Adenine pairs with Thymine and Cytosine pairs with Guanine in double-stranded DNA.
b) Total base pairs minus Adenine-Thymine pairs directly gives the number of Cytosine-Guanine pairs.

(xii) The stress hormone in plants which functions during a drought is: [1 Mark]
(a) Auxins
(b) Abscisic acid
(c) Ethylene
(d) Cytokinins

Answer: (b) Abscisic acid

Abscisic acid (ABA) acts as a plant stress hormone that induces stomatal closure during water stress conditions.

Teacher's Note:
a) ABA inhibits growth and promotes dormancy and abscission of leaves and fruits during unfavorable conditions.
b) It is widely known as the anti-transpirant hormone in plants.

(xiii) Compressed natural gas (CNG) is proposed to be a better alternative to fossil fuel. Which of the following reasons makes it a better alternative?
P. Combustion leaves little or no residue
Q. Absence of Carbon in CNG
R. Easily available [1 Mark]
(a) Only P
(b) Only Q
(c) Only P and R
(d) Only Q and R

Answer: (a) Only P

CNG combustion leaves little or no residue, making it cleaner. Statement Q is incorrect because CNG contains carbon (methane).

Teacher's Note:
a) Methane is the primary hydrocarbon component of CNG, which means carbon is present.
b) It burns cleanly, producing significantly fewer harmful emissions compared to petrol or diesel.

(xiv) The ground substance present in chloroplast is: [1 Mark]
(a) Stoma
(b) Stroma
(c) Grana
(d) Thylakoids

Answer: (b) Stroma

Stroma is the colorless proteinaceous ground substance enclosed by the inner membrane of a chloroplast.

Teacher's Note:
a) The dark reaction (Calvin cycle) of photosynthesis takes place within the stroma.
b) Be careful with spelling options like 'stoma' (plural stomata), which refer to leaf pores.

(xv) Lata wanted to cross the road. She looked on either side of the road and then walked across to the other side of the road.
Which of the following is / are involved in the process described above?
1. Cerebrum
2. Cerebellum
3. Skeletal muscles
4. Medulla Oblongata [1 Mark]
(a) Only 3
(b) Only 1 and 3
(c) Only 1, 3 and 4
(d) Only 1, 2 and 3

Answer: (d) Only 1, 2 and 3

Cerebrum processes visual input and decision-making, cerebellum coordinates voluntary muscular movement, and skeletal muscles execute walking.

Teacher's Note:
a) Voluntary actions and sensory interpretation involve the cerebrum and cerebellum, acting alongside skeletal muscles.
b) Medulla oblongata primarily controls involuntary vital functions like heartbeat and breathing, not voluntary locomotion.

Question 2

(i) Name the following: [5 Marks]
(a) The respiratory pigment in Erythrocytes.
(b) The tissue that transports manufactured food from the leaves to all the parts of the plant.
(c) The type of gene, which in the presence of a contrasting allele, is not expressed.
(d) The duct which carries urine from the urinary bladder to outside the body.
(e) The collective term for the protective membranes of the brain.

Answer:
(a) Haemoglobin
(b) Phloem
(c) Recessive gene
(d) Urethra
(e) Meninges

Teacher's Note:
a) Students must provide precise scientific terminology for each biological description.
b) Spelling errors for terms like 'Haemoglobin' or 'Meninges' may result in loss of marks.

(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) Snake, Grass, Frog, Grasshopper
(b) Cochlea, Malleus, Pinna, Stapes
(c) Fibrin, Thrombin, Fibrinogen, Platelets
(d) Endodermis, Cortex, Xylem, Epidermis
(e) Embryo, Foetus, Blastocyst, Morula

Answer:
(a) Grass -> Grasshopper -> Frog -> Snake
(b) Pinna -> Malleus -> Stapes -> Cochlea (or Malleus, Stapes sequence context)
(c) Platelets -> Fibrinogen -> Thrombin -> Fibrin
(d) Epidermis -> Cortex -> Endodermis -> Xylem
(e) Morula -> Blastocyst -> Embryo -> Foetus

Teacher's Note:
a) Ensure the sequence always starts strictly with the underlined term as instructed.
b) Check pathways and food chains carefully for logical directional flow.

(iii) Fill in the blanks with suitable words:
The technical term for short sightedness is (a) __________. This defect is caused because the eyeball is (b) __________ from front to back or the lens is too (c) __________. It can be corrected by using a suitable (d) __________ lens. The power of the lens is mentioned in (e) __________. [5 Marks]

Answer:
(a) Myopia
(b) elongated (or lengthened)
(c) curved / thick
(d) concave
(e) Dioptres

Teacher's Note:
a) Myopia is corrected using concave lenses which diverge light rays before they enter the eye.
b) Ensure proper technical vocabulary is used for filling in all blanks.

(iv) Choose the odd one out from the following terms and name the category to which the others belong: [5 Marks]
(a) Newspapers, Vegetable peels, Electric bulbs, Animal excreta
(b) Renal pelvis, Renal artery, Renal Cortex, Renal medulla
(c) Urochrome, Urea, Keratin, Uric acid
(d) Oval window, Cochlea, Auditory canal, Round window
(e) ADH, TSH, ACTH, NADP

Answer:
(a) Odd one out: Electric bulbs. Category: Biodegradable wastes.
(b) Odd one out: Renal artery. Category: Parts of the kidney.
(c) Odd one out: Keratin. Category: Excretory products.
(d) Odd one out: Auditory canal. Category: Parts of the inner ear.
(e) Odd one out: NADP. Category: Hormones.

Teacher's Note:
a) Both parts (identifying the odd one and naming the common category) are mandatory to get full credit.
b) Ensure the category title accurately describes all the remaining terms.

(v) Match the items given in Column I with the most appropriate ones in Column II and rewrite the correct matching pairs. [5 Marks]
Column I                          Column II
(a) Spinal Cord                  1. Adrenalin
(b) Adrenal medulla            2. 44
(c) Number of autosomes in man   3. Nephrons
(d) Kidney                       4. 46
(e) Adrenal cortex             5. Thyroxine
                                 6. Neurons
                                 7. Cortisones

Answer:
(a) Spinal Cord - 6. Neurons
(b) Adrenal medulla - 1. Adrenalin
(c) Number of autosomes in man - 2. 44
(d) Kidney - 3. Nephrons
(e) Adrenal cortex - 7. Cortisones

Teacher's Note:
a) Rewriting the complete matched pairs avoids ambiguity and ensures clear evaluation.
b) Double-check numerical counts and biological associations carefully.

SECTION B

Question 3

(i) The gene of red hair is recessive to the gene for black hair. What will be the hair colour of a person if he inherits a gene for red hair from his mother and a gene for black hair from his father? [1 Mark]

Answer:
Black hair.

Teacher's Note:
a) According to the Law of Dominance, the dominant allele expresses itself, masking the recessive allele.
b) The person will be heterozygous, carrying both alleles, but the phenotype will reflect only the dominant black hair trait.

(ii) State Mendel's Law of Dominance. [2 Marks]

Answer:
1. Out of a pair of contrasting alleles, only one is able to express itself while the other remains suppressed in an organism.
2. The allele that expresses itself is called the dominant allele, and the one that is suppressed is called the recessive allele.

Teacher's Note:
a) This law explains why F1 generation hybrids show only the dominant trait.
b) Keywords such as 'dominant allele', 'recessive allele', and 'expresses itself' must be included.

(iii) What are Homologous chromosomes? [2 Marks]

Answer:
1. Homologous chromosomes are a pair of chromosomes of the same shape, size, and gene sequence, one inherited from each parent.
2. They pair up during meiosis during synapsis.

Teacher's Note:
a) One chromosome of the homologous pair comes from the paternal side and the other from the maternal side.
b) Emphasize that they carry genes controlling the same set of hereditary characteristics.

(iv) Differentiate between Phenotype and Genotype. [2 Marks]

Answer:

Teacher's Note:
a) Always present differences in a tabular format for clarity.
b) Phenotype is what you see (appearance), whereas genotype is the genetic code behind it.

(v) Draw a neat, labelled diagram of a duplicated chromosome. [3 Marks]

Answer:
[Figure: Diagram of a duplicated chromosome showing two sister chromatids joined at the centromere, with labels for Centromere, Sister Chromatids, and Chromatid arms]
1. The diagram should clearly show two identical sister chromatids attached at a primary constriction called the centromere.
2. Proper labels for centromere and chromatids are essential.

Teacher's Note:
a) Neat pencil diagrams with clear, straight label lines score full marks.
b) Ensure the centromere is prominently marked as the point of attachment for sister chromatids.

Question 4

(i) Mention the exact location of Corpus callosum. [1 Mark]

Answer:
Corpus callosum is located at the floor of the longitudinal fissure, connecting the two cerebral hemispheres.

Teacher's Note:
a) It is a thick band of nerve fibers facilitating communication between the left and right cerebral hemispheres.
b) Precision in anatomical location is key to securing full marks.

(ii) What are the two hormones secreted by Corpus luteum? [2 Marks]

Answer:
1. Progesterone
2. Oestrogen

Teacher's Note:
a) Corpus luteum functions as a temporary endocrine structure formed after ovulation.
b) Progesterone maintains the uterine lining during pregnancy while oestrogen assists in secondary sexual characteristics and uterine lining proliferation.

(iii) Differentiate between Menarche and Menopause. [2 Marks]

Answer:

Teacher's Note:
a) Menarche marks the beginning of the reproductive phase in females.
b) Menopause signifies the end of the reproductive phase.

(iv) What is the significance of placenta in the growth of foetus? [2 Marks]

Answer:
1. It supplies oxygen and nutrients from the mother's blood to the foetus.
2. It removes metabolic wastes and carbon dioxide from the foetal blood.

Teacher's Note:
a) Placenta acts as a nutritive, respiratory, and excretory organ for the developing foetus.
b) Mentioning exchange of substances and endocrine function (secreting hormones) provides complete value points.

(v) Draw a neat, labelled diagram of a human gamete that has the sex chromosome Y. [3 Marks]

Answer:
[Figure: Diagram of a human Y-bearing sperm cell showing Acrosome, Head, Nucleus with Y chromosome, Middle piece with mitochondria, and Tail]
1. The sperm consists of head, middle piece, and tail.
2. The head contains the nucleus with the Y sex chromosome and is capped by the acrosome.

Teacher's Note:
a) Correct proportions and clear labelling of the acrosome, nucleus, middle piece containing mitochondria, and tail are required.
b) Indicate clearly that the nucleus carries the Y chromosome.

Question 5

(i) Explain the term - Photosynthesis. [1 Mark]

Answer:
Photosynthesis is the process by which green plants manufacture organic food (glucose) from carbon dioxide and water using sunlight energy trapped by chlorophyll, releasing oxygen as a byproduct.

Teacher's Note:
a) Ensure key components like sunlight, chlorophyll, carbon dioxide, and water are included.
b) Mentioning the conversion of light energy into chemical energy is a vital concept.

(ii) Write the overall chemical equation of Photosynthesis. [2 Marks]

Answer:
\( 6CO_2 + 6H_2O \xrightarrow[\text{Chlorophyll}]{\text{Sunlight}} C_6H_{12}O_6 + 6O_2 \)

Teacher's Note:
a) The equation must be balanced to receive full credit.
b) Sunlight and chlorophyll must be clearly indicated above and below the reaction arrow.

(iii) A potted plant having variegated leaves was exposed to sunlight for 3 hours. One of the leaves was plucked and tested for starch. What will be your observation after the starch test? [2 Marks]

Answer:
1. The green parts of the leaf turn blue-black with iodine solution, indicating starch presence.
2. The non-green (yellow or white) parts of the leaf remain brown or yellowish-orange, showing absence of starch.

Teacher's Note:
a) Variegated leaves have patches with and without chlorophyll.
b) This experiment proves that chlorophyll is essential for photosynthesis.

(iv) The initial food prepared by a green plant is A, which is later converted to food B by polymerization. Name food A and food B. [2 Marks]

Answer:
Food A: Glucose
Food B: Starch

Teacher's Note:
a) Glucose is the immediate soluble product of photosynthesis.
b) Excess glucose is polymerized and stored in an insoluble form as starch.

(v) Study the diagram given below and answer the questions that follow:
(a) Name the gas released when the setup was placed in sunlight.
(b) Give an example of an aquatic plant that can be used in the above experiment.
(c) What will happen if a pinch of Sodium bicarbonate is added to the water? [3 Marks]

[Figure: Experimental setup showing an inverted funnel over aquatic plants in a beaker of water with a test tube collecting gas bubbles at the top under a light source]

Answer:
(a) Oxygen gas (\(O_2\))
(b) Hydrilla (or Vallisneria / Elodea)
(c) It increases the dissolved carbon dioxide concentration in water, thereby increasing the rate of photosynthesis and oxygen bubble evolution.

Teacher's Note:
a) This classic experiment demonstrates that oxygen is evolved during photosynthesis.
b) Sodium bicarbonate acts as a ready source of carbon dioxide for submerged aquatic plants.

Question 6

(i) Give the exact location of genes. [1 Mark]

Answer:
Genes are located linearly on chromosomes within the nucleus of a cell.

Teacher's Note:
a) They occupy specific positions known as loci on chromosomes.
b) Mentioning chromosomes inside the nucleus is essential for precision.

(ii) Differentiate between Karyokinesis and Cytokinesis. [2 Marks]

Answer:

Teacher's Note:
a) Karyokinesis involves prophase, metaphase, anaphase, and telophase.
b) Cytokinesis differs in mechanism between plant cells (cell plate formation) and animal cells (furrowing).

(iii) Mention two significant features of the stage Anaphase during Mitosis. [2 Marks]

Answer:
1. The centromere splits, separating the sister chromatids.
2. Daughter chromatids move towards opposite poles of the cell due to the shortening of spindle fibers.

Teacher's Note:
a) Anaphase is the shortest phase of mitosis.
b) Mentioning the splitting of the centromere and movement of chromosomes to opposite poles fetches full marks.

(iv) How many daughter cells are formed at the end of Mitosis and Meiosis? [2 Marks]

Answer:
1. Mitosis: Two genetically identical daughter cells are formed.
2. Meiosis: Four genetically distinct daughter cells are formed.

Teacher's Note:
a) Mitosis results in diploid daughter cells (in most cases) maintaining chromosome number.
b) Meiosis results in haploid daughter cells reducing the chromosome number by half.

(v) Study the diagram given below and answer the questions that follow:
(a) Name the phenomenon depicted by the shoot in the above diagram.
(b) Which plant hormone plays an important role in the above movement?
(c) Name one stimulus which gives a positive response for the roots but negative response for the shoot. [3 Marks]

[Figure: Potted plant bending towards a directional light source entering through a window opening]

Answer:
(a) Phototropism (positive phototropism)
(b) Auxin
(c) Gravity (Geotropism)

Teacher's Note:
a) Phototropism is the directional growth movement of plant organs in response to light.
b) Unequal distribution of auxins causes the shaded side of the stem to grow faster than the illuminated side, leading to bending towards light.

Question 7

(i) What is the scientific name for man? [1 Mark]

Answer:
Homo sapiens

Teacher's Note:
a) Binomial nomenclature rules require the genus name to start with a capital letter and species name with a small letter.
b) It is standard practice to italicize or underline scientific names when handwritten.

(ii) What are vestigial organs? Give one example. [2 Marks]

Answer:
1. Vestigial organs are non-functional, reduced, or rudimentary organs that were fully developed and functional in ancestral forms.
2. Example: Vermiform appendix (or nictitating membrane / wisdom teeth).

Teacher's Note:
a) Vestigial organs provide significant anatomical evidence supporting organic evolution.
b) Ensure both definition and a correct example are provided.

(iii) State two structural differences between an artery and vein. [2 Marks]

Answer:

Teacher's Note:
a) Differences in wall thickness and presence of valves are key structural distinctions.
b) Tabular presentation ensures clarity and completeness.

(iv) Mention any two features of the Cro-Magnon man. [2 Marks]

Answer:
1. They had a large cranial capacity (about 1600 cc), which is even larger than that of modern humans.
2. They possessed a prominent chin, high forehead, and well-developed speech centers.

Teacher's Note:
a) Cro-Magnon man is considered an extinct subspecies of modern humans (*Homo sapiens fossils*).
b) They were skilled cave dwellers and artists.

(v) Study the picture given below and answer the questions that follow:
(a) Name the category of waste that is being disposed.
(b) Give an example of such a waste.
(c) Are they hazardous to humans and animals? Give a suitable reason to justify your answer. [3 Marks]

[Figure: Dustbin containing biomedical waste items such as used syringes, surgical gloves, face masks, and medicine vials]

Answer:
(a) Biomedical waste (clinical waste)
(b) Used syringes, needles, or bandages.
(c) Yes, they are hazardous because they can transmit infectious diseases, harbor pathogens, and cause accidental injuries or toxic contamination if disposed of improperly.

Teacher's Note:
a) Biomedical wastes require specialized disposal methods like incineration or autoclaving.
b) Clearly state both the hazardous nature and the reasoning regarding infection transmission.

Question 8

(i) Define - Osmosis. [1 Mark]

Answer:
Osmosis is the movement of water molecules from a region of higher water concentration (dilute solution) to a region of lower water concentration (concentrated solution) through a semi-permeable membrane.

Teacher's Note:
a) Mentioning the semi-permeable membrane and the concentration gradient is crucial.
b) Students must not confuse osmosis with diffusion.

(ii) Name the two sensory cells in retina meant for light adaptation. [2 Marks]

Answer:
1. Rod cells (responsible for dim-light vision)
2. Cone cells (responsible for bright-light and color vision)

Teacher's Note:
a) Rods contain rhodopsin pigment and function in low light.
b) Cones contain iodopsin pigment and function in bright light, providing color perception.

(iii) Mention one function each for - Cerebrum and Cerebellum. [2 Marks]

Answer:
1. Cerebrum: Controls voluntary actions, memory, intelligence, and interprets sensory impulses.
2. Cerebellum: Coordinates voluntary muscular movements and maintains body balance and posture.

Teacher's Note:
a) Cerebrum is the seat of consciousness and higher mental functions.
b) Cerebellum ensures smooth and synchronized muscle activity.

(iv) State any two objectives of Swachh Bharat Abhiyan. [2 Marks]

Answer:
1. To eliminate open defecation by constructing household and community toilets.
2. To improve solid and liquid waste management practices across rural and urban areas.

Teacher's Note:
a) Swachh Bharat Abhiyan is a national cleanliness campaign launched by the Government of India.
b) Mentioning sanitation, waste management, or behavioral change towards hygiene secures full marks.

(v) Given below is the diagram of human blood smear. Answer the questions that follow:
(a) Mention one structural difference between 1 and 2.
(b) What is the function of part 3?
(c) Name the part labelled 4. [3 Marks]

[Figure: Diagram of blood smear showing 1 (RBC - biconcave disc), 2 (WBC with lobed nucleus), 3 (Blood platelet), and 4 (Plasma matrix)]

Answer:
(a) Part 1 (Erythrocyte) is circular, biconcave, and lacks a nucleus, whereas Part 2 (Leucocyte) is amoeboid and possesses a prominent nucleus.
(b) Part 3 (Platelet / Thrombocyte) helps in the clotting of blood.
(c) Part 4: Blood plasma

Teacher's Note:
a) Careful observation of cellular components in blood smears is tested in this question.
b) Ensure labels correspond correctly to RBC, WBC, platelets, and plasma.