Biology MCQ Practice 27 — Science Foundation Course for Class 11 & 12

1. The smallest unit that can evolve is:

(a) Individual (b) Population (c) Species (d) Community

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Correct Answer: (b) Population

Explanation:
Evolution occurs at the population level through changes in allele frequencies

2. The enzyme that joins DNA fragments is:

(a) DNA polymerase (b) Ligase (c) Helicase (d) Restriction endonuclease

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Correct Answer: (b) Ligase

Explanation:
DNA ligase joins DNA fragments (e.g., in recombinant DNA technology)

3. The hormone that stimulates milk production is:

(a) Oxytocin (b) Prolactin (c) Estrogen (d) Progesterone

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Correct Answer: (b) Prolactin

Explanation:
Prolactin stimulates milk production (lactation)

4. The tissue that provides buoyancy to aquatic plants is:

(a) Parenchyma (b) Aerenchyma (c) Collenchyma (d) Sclerenchyma

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Correct Answer: (b) Aerenchyma

Explanation:
Aerenchyma has air spaces for buoyancy and gaseous exchange

5. The process by which organisms maintain internal conditions is called:

(a) Homeostasis (b) Adaptation (c) Evolution (d) Mutation

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Correct Answer: (a) Homeostasis

Explanation:
Homeostasis is the maintenance of stable internal conditions

6. The functional unit of the nervous system is:

(a) Nephron (b) Neuron (c) Alveolus (d) Sarcomere

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Correct Answer: (b) Neuron

Explanation:
Neuron is the structural and functional unit of the nervous system

7. The pigment that gives colour to human skin is:

(a) Haemoglobin (b) Melanin (c) Chlorophyll (d) Carotene

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Correct Answer: (b) Melanin

Explanation:
Melanin is produced by melanocytes

8. The largest part of the human brain is:

(a) Cerebellum (b) Cerebrum (c) Medulla oblongata (d) Hypothalamus

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Correct Answer: (b) Cerebrum

Explanation:
Cerebrum controls voluntary actions and higher functions

9. The process of fusion of male and female gametes is called:

(a) Pollination (b) Fertilisation (c) Implantation (d) Gestation

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Correct Answer: (b) Fertilisation

Explanation:
Fertilisation forms the zygote

10. The functional unit of muscle contraction is:

(a) Neuron (b) Nephron (c) Alveolus (d) Sarcomere

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Correct Answer: (d) Sarcomere

Explanation:
Sarcomere is the basic unit of striated muscle contraction