1. Structural and functional unit of the nervous system is:
A. Nephron
B. Neuron
C. Axon
D. Dendrite
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Answer: B. Neuron
Explanation: Neurons are specialized nerve cells that transmit electrical impulses throughout the nervous system.
2. Which part of the neuron receives chemical signals from surrounding environment or adjacent cells?
A. Axon
B. Dendrite
C. Nerve ending
D. Cell body
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Answer: B. Dendrite
Explanation: Fine branch-like dendrites acquire information and trigger electrical impulses toward the cell body.
3. The microscopic gap between two adjacent neurons where nerve impulse is transmitted chemically is called:
A. Axon
B. Synapse
C. Dendrite
D. Myelin sheath
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Answer: B. Synapse
Explanation: Electrical signals release neurotransmitter chemicals across the synapse gap to generate electrical signals in next dendrite.
4. Automatic, rapid, and involuntary response to a stimulus without conscious thinking is called:
A. Voluntary action
B. Reflex action
C. Phototropism
D. Nastic movement
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Answer: B. Reflex action
Explanation: Reflex actions are immediate, automatic protective movements controlled at spinal cord level.
5. Reflex arcs are formed in which central structure of the nervous system?
A. Brain
B. Spinal Cord
C. Heart
D. Liver
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Answer: B. Spinal Cord
Explanation: Reflex arcs link sensory inputs directly to motor outputs inside the spinal cord for ultra-fast reaction times.
6. The main thinking part of the human brain is the:
A. Forebrain (Cerebrum)
B. Midbrain
C. Cerebellum
D. Medulla
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Answer: A. Forebrain (Cerebrum)
Explanation: The forebrain processes sensory information, thinking, memory, intelligence, and voluntary actions.
7. Which part of the hindbrain controls posture, balance, and precision of voluntary movements?
A. Medulla
B. Pons
C. Cerebellum
D. Hypothalamus
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Answer: C. Cerebellum
Explanation: Cerebellum coordinates muscular activities like walking straight, riding a bicycle, or picking up a pencil.
8. Involuntary actions such as blood pressure, salivation, and vomiting are controlled by:
A. Cerebrum
B. Cerebellum
C. Medulla in hindbrain
D. Spinal cord
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Answer: C. Medulla in hindbrain
Explanation: The medulla oblongata governs vital involuntary life-support functions automatically.
9. The central nervous system (CNS) consists of:
A. Brain and Spinal Cord
B. Cranial nerves and Spinal nerves
C. Autonomic nervous system only
D. Sympathetic and Parasympathetic nerves
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Answer: A. Brain and Spinal Cord
Explanation: CNS comprises the brain and spinal cord, which collect, process, and integrate neural information.
10. Brain is safely enclosed inside a bony box called:
A. Vertebral column
B. Cranium (Skull)
C. Sternum
D. Rib cage
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Answer: B. Cranium (Skull)
Explanation: Cranium protects delicate brain tissue alongside shock-absorbing cerebrospinal fluid.
11. Directional growth movement of a plant part in response to light stimulus is called:
A. Geotropism
B. Phototropism
C. Hydrotropism
D. Chemotropism
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Answer: B. Phototropism
Explanation: Stems show positive phototropism growing towards light, while roots show negative phototropism.
12. Growth of pollen tube towards ovules during fertilization is an example of:
A. Phototropism
B. Geotropism
C. Chemotropism
D. Thigmotropism
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Answer: C. Chemotropism
Explanation: Chemotropism is plant directional growth in response to chemical signals released inside flower pistil.
13. Which plant hormone promotes cell elongation and causes shoot tips to bend towards light?
A. Cytokinin
B. Auxin
C. Abscisic Acid
D. Ethylene
Show Answer
Answer: B. Auxin
Explanation: Auxin accumulates on the shaded side of shoot tip, stimulating faster elongation there to bend stem towards light.
14. Plant hormone that promotes rapid cell division and is present in high concentrations in seeds and fruits is:
A. Auxin
B. Gibberellin
C. Cytokinin
D. Abscisic acid
Show Answer
Answer: C. Cytokinin
Explanation: Cytokinins trigger active cell division in rapidly growing plant regions like fruits, seeds, and root tips.
15. Which plant hormone acts as a growth inhibitor, causing wilting of leaves and seed dormancy?
A. Auxin
B. Gibberellin
C. Cytokinin
D. Abscisic acid (ABA)
Show Answer
Answer: D. Abscisic acid (ABA)
Explanation: Abscisic acid stops growth, closes stomata under drought stress, and causes leaf drop (abscission).
16. Drooping of leaves in 'Touch-Me-Not' plant (Mimosa pudica) on touching is a non-directional movement known as:
A. Tropic movement
B. Nastic movement (Thigmonasty)
C. Phototropic movement
D. Geotropic movement
Show Answer
Answer: B. Nastic movement (Thigmonasty)
Explanation: Nastic movements depend on turgor pressure changes inside leaf base cells regardless of stimulus direction.
17. Iodine is necessary in human diet for the synthesis of which hormone by the thyroid gland?
A. Insulin
B. Thyroxin
C. Adrenaline
D. Growth hormone
Show Answer
Answer: B. Thyroxin
Explanation: Thyroid gland requires iodine to synthesize thyroxin, regulating carbohydrate, protein, and fat metabolism.
18. Deficiency of iodine in human diet causes a disease known as:
A. Diabetes
B. Goitre
C. Dwarfism
D. Anemia
Show Answer
Answer: B. Goitre
Explanation: Lack of iodine causes enlargement of thyroid gland leading to swollen neck condition called goitre.
19. Hormone responsible for regulating blood sugar levels in the human body is:
A. Thyroxin
B. Insulin
C. Adrenaline
D. Estrogen
Show Answer
Answer: B. Insulin
Explanation: Insulin lowers blood glucose level by facilitating cell uptake and glycogen conversion.
20. Which organ in the human body secretes insulin hormone?
A. Liver
B. Thyroid
C. Pancreas
D. Pituitary
Show Answer
Answer: C. Pancreas
Explanation: Beta cells in islets of Langerhans inside pancreas secrete insulin directly into blood.
21. Deficiency of insulin hormone causes which medical condition?
A. Goitre
B. Diabetes mellitus
C. Gigantism
D. Scurvy
Show Answer
Answer: B. Diabetes mellitus
Explanation: Insufficient insulin output elevates blood sugar levels, causing diabetes mellitus.
22. Which gland is known as the "Master Gland" of the endocrine system?
A. Thyroid gland
B. Adrenal gland
C. Pituitary gland
D. Pancreas
Show Answer
Answer: C. Pituitary gland
Explanation: Pituitary gland secretes tropic hormones that control functions of other endocrine glands.
23. Hormone secreted during emergency/frightening situations ("Fight or Flight" hormone) is:
A. Thyroxin
B. Adrenaline
C. Insulin
D. Growth hormone
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Answer: B. Adrenaline
Explanation: Adrenal glands release adrenaline under stress to increase heart rate, breathing, and muscle blood flow.
24. Hyposecretion (under-secretion) of Growth Hormone in childhood leads to:
A. Gigantism
B. Dwarfism
C. Goitre
D. Diabetes
Show Answer
Answer: B. Dwarfism
Explanation: Pituitary growth hormone promotes skeletal development; deficiency retards height growth.
25. Male sex hormone responsible for secondary sexual characteristics in boys during puberty is:
A. Estrogen
B. Progesterone
C. Testosterone
D. Insulin
Show Answer
Answer: C. Testosterone
Explanation: Testes secrete testosterone which regulates sperm formation and puberty changes in males.
26. Female sex hormone produced by ovaries that regulates female secondary sexual changes is:
A. Testosterone
B. Estrogen
C. Adrenaline
D. Thyroxin
Show Answer
Answer: B. Estrogen
Explanation: Ovaries secrete estrogen driving secondary sexual characteristics and reproductive development in females.
27. Receptor cells present in taste buds that detect taste signals are called:
A. Olfactory receptors
B. Gustatory receptors
C. Photoreceptors
D. Phonoreceptors
Show Answer
Answer: B. Gustatory receptors
Explanation: Gustatory receptors detect taste chemicals, while olfactory receptors in nose detect smell.
28. Mechanism that regulates the timing and amount of hormone release in human body is called:
A. Reflex arc
B. Feedback mechanism
C. Translocation
D. Peristalsis
Show Answer
Answer: B. Feedback mechanism
Explanation: Negative feedback loops monitor circulating blood hormone/nutrient levels to turn secretion on or off.
29. Downward growth of roots towards earth in response to gravity is an example of:
A. Positive Phototropism
B. Positive Geotropism
C. Negative Geotropism
D. Hydrotropism
Show Answer
Answer: B. Positive Geotropism
Explanation: Roots grow downwards in direction of gravitational pull (positive geotropism).
30. Stem tendrils twining around a support on contact show which tropism?
A. Hydrotropism
B. Thigmotropism
C. Chemotropism
D. Geotropism
Show Answer
Answer: B. Thigmotropism
Explanation: Thigmotropism is directional plant growth movement in response to touch contact with physical objects.
