BioNotesICSE Class X Biology Practice Paper 1 - Question Paper
Practice question paper (80 marks, 2 hours) for ICSE Class X Biology, Science Paper 3, 2027 pattern.
ICSE Class X Biology Practice Paper 2 - Question Paper
Practice question paper (80 marks, 2 hours) for ICSE Class X Biology, Science Paper 3, 2027 pattern.
Created by Titas Mallick
Biology Teacher • M.Sc. Botany • B.Ed. • CTET (CBSE) • CISCE Examiner
Online
Marking scheme and model answers for ICSE Class X Biology Practice Paper 2, 2027 pattern.
Marks are awarded point-wise, in the manner of CISCE step-marking. Alternative correct answers should be accepted.
| Q | Answer | Q | Answer | Q | Answer |
|---|---|---|---|---|---|
| (i) | (c) hypertonic solution | (vi) | (c) P, Q and S | (xi) | (b) ADH |
| (ii) | (c) Both true, R correct explanation | (vii) | (c) 46 and 92 | (xii) | (a) 9 : 3 : 3 : 1 |
| (iii) | (d) ethylene | (viii) | (b) semicircular canals | (xiii) | (a) decreases |
| (iv) | (b) Rh-negative mother, Rh-positive foetus | (ix) | (c) Both true, R correct explanation | (xiv) | (b) Darwin's theory of natural selection |
| (v) | (b) iodine | (x) | (d) AB | (xv) | (b) 2% |
Working notes:
(i) [5 × 1]
(a) Bleeding
(b) Macula lutea (yellow spot) / fovea
(c) Adrenaline
(d) Parturition
(e) Metaphase
(ii) [5 × 1]
(a) potassium
(b) endosmosis
(c) turgid
(d) open
(e) flaccid
(iii) [5 × 1] (½ mark for odd one out + ½ mark for category)
| Odd one out | Category of remaining three | |
|---|---|---|
| (a) | Erythrocytes | White blood cells (leucocytes) |
| (b) | Insulin | Sex hormones |
| (c) | Cornea | Parts of the ear |
| (d) | Salivary gland | Endocrine glands |
| (e) | Sulphur dioxide | Greenhouse gases |
(iv) [5 × 1]
(a) Myopia (short-sightedness)
(b) Any one: elongation of the eyeball; the eye lens being too convex/thick.
(c) Concave (diverging) lens
(d) In front of the retina
(e) Ciliary muscles
(v) [5 × 1]
Gibberellin – (e); Cytokinin – (a); Abscisic acid – (c); Ethylene – (b); Thigmotropism – (d).
(i) [1] To show that the rate of transpiration is unequal on the two surfaces of a dorsiventral leaf.
(ii) [2] The blue paper turns pink [1], as cobalt chloride absorbs the water vapour released by the leaf [1].
(iii) [2] The paper on the lower surface turns pink faster [1], since the lower epidermis has more stomata than the upper epidermis [1].
(iv) [2] To prevent water vapour from the atmosphere from affecting the paper [1], and to keep the paper in close contact with the leaf surface [1].
(v) [3] 1 mark for correct diagram, 2 marks for any four correct labels. Expected labels: Bell jar, Potted plant, Polythene sheet covering the pot (soil), Glass plate, Vaseline (airtight seal), Water droplets on the inner wall of the bell jar.
(i) [1] Left ventricle.
(ii) [2] The left ventricle pumps blood to the whole body, which requires a high pressure [1]; the right ventricle pumps blood only to the nearby lungs, so a thinner wall is sufficient [1].
(iii) [2] Bicuspid (mitral) valve [1]. It allows blood to flow from the left auricle to the left ventricle and prevents backflow [1].
(iv) [2] Double circulation: blood passes through the heart twice in one complete circuit of the body — once through the pulmonary circuit and once through the systemic circuit [1]. Advantage: oxygenated and deoxygenated blood do not mix, ensuring efficient supply of oxygen to tissues [1].
(v) [3] 1 mark for correct diagram, 2 marks for any four correct labels.
www.bionotes.inLabels: Right atrium (auricle), Right ventricle, Left atrium (auricle), Left ventricle, Aorta, Pulmonary artery, Superior vena cava, Inferior vena cava, Bicuspid valve, Tricuspid valve, Septum.
(i) [1] Diabetes mellitus.
(ii) [2] Insulin [1]; secreted by the pancreas (β-cells of the islets of Langerhans) [1].
(iii) [2] When blood glucose rises, insulin converts excess glucose into glycogen in the liver and muscles [1]. When blood glucose falls, glucagon converts glycogen back into glucose, raising the level [1].
(iv) [2] (any two)
| Endocrine glands | Exocrine glands |
|---|---|
| Ductless | Have ducts |
| Secretions (hormones) are released directly into the blood | Secretions are carried through ducts to the site of action |
| Examples: pituitary, thyroid, adrenal | Examples: salivary glands, sweat glands |
(v) [3] (a) Cretinism [1]; (b) Acromegaly [1]; (c) Diabetes insipidus [1].
(i) [1] A reflex action is a sudden, involuntary and automatic response to a stimulus.
(ii) [2] Receptor → sensory neuron → spinal cord (relay neuron) → motor neuron → effector (muscle/gland). (All five stages in correct order for 2 marks; 1 mark if one stage is missed.)
(iii) [2] (a) Cerebellum: maintains balance/posture and coordinates voluntary muscular movements [1]; (b) Medulla oblongata: controls involuntary actions such as heartbeat, breathing, and swallowing/vomiting [1].
(iv) [2]
| Natural reflex | Acquired reflex |
|---|---|
| Inborn, does not need learning | Developed by learning/experience |
| Example: withdrawing hand from a hot object | Example: salivation at the sight of food |
(v) [3] 1 mark for correct diagram, 2 marks for any four correct labels.
www.bionotes.inLabels: Dendrites, Cell body (cyton/soma), Nucleus, Axon, Myelin sheath, Node of Ranvier, Schwann cell, Axon terminals (synaptic knobs).
(i) [1] About 28 days.
(ii) [2] (a) Testosterone [1]; (b) Oestrogen [1].
(iii) [2] (a) Implantation: the embedding of the blastocyst in the endometrium (uterine wall) [1]; (b) Gestation: the period from fertilisation to birth (about 40 weeks / 9 months) [1].
(iv) [2] (any two) Supplies nutrients and oxygen to the foetus; removes excretory waste (CO₂ and urea) from the foetus; secretes hormones (hCG, oestrogen, progesterone); acts as a barrier against some harmful substances.
(v) [3] 1 mark for correct diagram, 2 marks for any four correct labels.
www.bionotes.inLabels: Head, Acrosome, Nucleus, Middle piece, Mitochondria, Centriole, Tail.
(i) [1] Jean-Baptiste Lamarck.
(ii) [2] Before industrialisation, light-coloured moths were camouflaged on lichen-covered tree trunks, while dark moths were easily eaten by birds [1]. After industrial pollution blackened the tree trunks, dark moths were better camouflaged and survived, while light moths were eaten; hence the dark form increased (survival of the fittest) [1].
(iii) [2] (any two) Bipedalism/erect posture; increase in cranial capacity; reduction in size of canine teeth; reduction of brow ridges; development of chin; reduction in body hair.
(iv) [2] (a) Demography: the statistical study of human populations (size, density, birth and death rates, etc.) [1]; (b) Population density: the number of individuals per unit area [1].
(v) [3] (any three) Unemployment; over-exploitation of natural resources; low per capita income; rise in prices; pollution; unequal distribution of wealth; shortage of food, housing and healthcare.
Diagrams in the marking scheme are from the BioNotes diagram bank. Question–answer design by the BioNotes teaching team; syllabus alignment: CISCE ICSE 2027 Biology (Science Paper 3).
ICSE Class X Biology Practice Paper 1 - Question Paper
Practice question paper (80 marks, 2 hours) for ICSE Class X Biology, Science Paper 3, 2027 pattern.
ICSE Class X Biology Practice Paper 2 - Question Paper
Practice question paper (80 marks, 2 hours) for ICSE Class X Biology, Science Paper 3, 2027 pattern.