Class 10 Science · Chapter 6

Control and Coordination

286 Class 10 Science questions on Control and Coordination from the NCERT textbook, NCERT Exemplar and CBSE board papers 2018–2026, each with its answer and a step-by-step solution.

NCERT exercises

Exercises (12) Intext Questions (Page 105) (5) Intext Questions (Page 108) (5) Intext Questions (Page 111) (4)

NCERT Exemplar exercises

Multiple Choice Questions (33) Short Answer Questions (11) Long Answer Questions (9)

CBSE Class 10 Science previous year papers, with answers →

Questions · page 9 of 15

Q161 CBSE 2025
A person while climbing up a rocky hill comes into a panic state and fear. His body starts reacting in a “flight-or-flight” condition to adjust to the dangerous and stressful situation. Based on the above facts, answer the questions that follow.
1. (a)(i)Name the hormone secreted in the blood of the person in this situation.[2]
2. (a)(ii)OR : Name the source gland of the hormone secreted in this condition.[2]
3. (b)State any two responses in the body of the person as a result of the secretion of this hormone.[1]
4. (c)How does the action of the chemical signal in terms of hormones differ from the electrical impulses via nerve cells?[1]
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Adrenaline, from the adrenal medulla; it speeds the heartbeat and breathing; hormones act slower but longer and wider than nerve impulses.
(a)(i) The hormone secreted into the blood is adrenaline (epinephrine). (a)(ii) Its source gland is the adrenal gland - specifically the adrenal medulla, one gland sitting on top of each kidney. (Only one of these two branches is to be attempted.) (b) Any two of: the heart beats faster, so more oxygenated blood reaches the muscles; the breathing rate increases because the diaphragm and rib muscles contract faster; the small arteries of the skin and digestive system are constricted, diverting blood to the skeletal muscles; the pupils dilate. (c) A hormone is a chemical released into the blood, so it travels more slowly but is carried to every part of the body and acts on all cells having receptors for it, whether or not a nerve reaches them, and its effect is steady and persistent. An electrical impulse travels only along nerve fibres, so it reaches only the cells connected by nervous tissue; it is very fast but short-lived, and the nerve cell must reset itself before it can transmit another impulse.

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Q162 CBSE 2025
In life there are certain changes in the environment called ‘stimuli’ to which we respond appropriately. Touching a flame suddenly is a dangerous situation for us. One way is to think consciously about the possibility of burning and then moving the hand. But our body has been designed in such a way that we save ourself from such situations immediately.
1. (i)Name the action by which we protect ourself in the situation mentioned above and define it.[1]
2. (ii)Write the role of (a) motor and (b) relay neuron.[1]
3. (iii)(A)What are the two types of nervous system in human body? Name the components of each of them.[2]
4. (iii)(B)OR : Which part of the human brain is responsible for : (a) thinking (b) picking up a pencil (c) controlling blood pressure (d) controlling hunger[2]
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Reflex action is an involuntary response via the spinal cord; motor neurons carry it to the muscle; the nervous system has CNS and PNS.
(i) Reflex action - a sudden, rapid, automatic and involuntary response of the body to a stimulus, carried out through a reflex arc in the spinal cord without the conscious part of the brain being involved. (ii)(a) The motor neuron carries the impulse away from the spinal cord to the effector - the arm muscle - which contracts and pulls the hand back. (b) The relay neuron lies inside the spinal cord and links the sensory neuron to the motor neuron, completing the reflex arc. (iii)(A) The two types are the central nervous system, whose components are the brain and the spinal cord, and the peripheral nervous system, whose components are the cranial nerves arising from the brain and the spinal nerves arising from the spinal cord. (iii)(B) (a) thinking - the cerebrum of the fore-brain; (b) picking up a pencil - the cerebellum of the hind-brain; (c) controlling blood pressure - the medulla of the hind-brain; (d) controlling hunger - the hunger centre of the fore-brain, the hypothalamus.

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Q163 CBSE 2025
The growth movements of plant parts in which the direction of the stimulus determines the direction of the response is known as tropic movements or tropism. Plants also have non-directional movements which may not be growth dependent.
1. (I)Name the movement which causes ‘X’ and ‘Y’ to grow downwards and upwards respectively. (Refer above figure)[1]
2. (II)Write the name of a hormone that plays a major role in (i) falling of leaves (ii) rapid cell division[1]
3. (III)(a)Leaves of the sensitive plant move very quickly in response to ‘touch’. How is this stimulus of touch communicated and explain how the movement takes place.[2]
4. (III)(b)OR : Name the plant hormone which is synthesized at the shoot tip. How does this hormone helps the plant to bend towards light ?[2]
Show answer

Geotropism; abscisic acid and cytokinin; touch-sensitive leaves fold by losing water; auxin bends shoots towards light.
(I) Geotropism (gravitropism): the root X shows positive geotropism by growing towards gravity and the shoot Y shows negative geotropism by growing away from it. (II) (i) Abscisic acid; (ii) Cytokinin. (III)(a) Plants have no nerves, so the touch is passed from cell to cell as an electrical and chemical signal. The cells at the base of the leaflets then lose water, shrink and lose their swollen shape, so the leaflets fold and droop; when water returns they swell again and the leaflets reopen. The movement is not caused by growth. (III)(b) Auxin. Made at the shoot tip, it diffuses towards the shaded side when light comes from one side. The cells on that shaded side then grow longer than those on the lit side, and this unequal growth bends the shoot towards the light.

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Q164 CBSE 2024
A plant growth inhibitor hormone which causes wilting of leaves is called :
1. (a)Auxin
2. (b)Cytokinin
3. (c)Abscisic acid
4. (d)Gibberellin
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(c) Abscisic acid

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Q165 CBSE 2024
The correct sequence of events when someone’s hand touches a hot object unconsciously :
1. (a)Receptors in skin → Motor neuron → Relay neuron → Sensory neuron → Effector muscle in arm
2. (b)Receptors in skin → Relay neuron → Sensory neuron → Motor neuron → Effector muscle in arm
3. (c)Receptors in skin → Sensory neuron → Relay neuron → Motor neuron → Effector muscle in arm
4. (d)Receptors in skin → Sensory neuron → Effector muscle in arm → Motor neuron → Relay neuron
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(c) Receptors in skin → Sensory neuron → Relay neuron → Motor neuron → Effector muscle in arm

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Q166 CBSE 2024
Identify an involuntary action from the following :
1. (a)Riding a bicycle
2. (b)Picking up a pencil
3. (c)Regular beating of heart
4. (d)Walking in a straight line
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(c) Regular beating of heart

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Q167 CBSE 2024
Select from the following a plant hormone which promotes cell division.
1. (a)Gibberellins
2. (b)Auxins
3. (c)Abscissic Acid
4. (d)Cytokinins
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(d) Cytokinins

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Q168 CBSE 2024
Sense organ in which olfactory receptors are present is :
1. (a)Nose
2. (b)Skin
3. (c)Tongue
4. (d)Inner ear
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(a) Nose

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Q169 CBSE 2024
Select a pair of plant hormones from the following :
1. (a)Cytokinin and Insulin
2. (b)Gibberellin and Adrenaline
3. (c)Abscisic acid and Adrenaline
4. (d)Auxin and Abscisic acid
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(d) Auxin and Abscisic acid

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Q170 CBSE 2024
Select out of the following a gland which does NOT occur as a pair in the human body :
1. (a)Pituitary
2. (b)Ovary
3. (c)Testis
4. (d)Adrenal
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(a) Pituitary

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Q171 CBSE 2024
A doctor advised a person to take an injection of insulin because :
1. (a)his heart was beating slowly.
2. (b)his blood pressure was low.
3. (c)he was looking short in height.
4. (d)his pancreas was not secreting the required hormone in proper amounts.
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(d) his pancreas was not secreting the required hormone in proper amounts.

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Q172 CBSE 2024
Olfactory receptors are able to detect :
1. (a)touch
2. (b)taste
3. (c)smell
4. (d)light
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(c) smell

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Q173 CBSE 2024
In a nerve cell, the site where the electrical impulse is converted into a chemical signal is known as :
1. (a)Axon
2. (b)Dendrites
3. (c)Neuromuscular junction
4. (d)Cell body
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(a) Axon

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Q174 CBSE 2024
The part of human brain which controls muscular coordination is :
1. (a)medulla
2. (b)pons
3. (c)cerebrum
4. (d)cerebellum
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(d) cerebellum

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Q175 CBSE 2024
The movement of sunflowers is in response to a stimulus such as :
1. (a)gravity
2. (b)chemicals
3. (c)day or night
4. (d)water
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(c) day or night

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Q176 CBSE 2024
Which of the following statements is/are true about a neuron ? I. Dendrites of neuron pass the impulse to the axon. II. Axon of neuron carries the impulse from the cell body. III. Sensory neuron carries the impulse to the specific effectors. IV. Transmission of impulse from a neuron to a muscle fibre occurs through neuro-muscular junction.
1. (a)I only
2. (b)I and III
3. (c)II and III
4. (d)II and IV
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(d) II and IV

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Q177 CBSE 2024
In a nerve cell (neuron), the conversion of electrical signal to chemical signal occurs in/at :
1. (a)dendritic end
2. (b)cell body
3. (c)axon
4. (d)axonal end
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(d) axonal end

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Q178 CBSE 2024
Two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to this question from the codes (a), (b), (c) and (d) as given below.
Assertion (A): Chemical co-ordination is seen in both plants and animals.
Reason (R): Plant hormones control directional growth, whereas in animals, growth is never seen in one direction only.
1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
3. (c)Assertion (A) is true, but Reason (R) is false.
4. (d)Assertion (A) is false, but Reason (R) is true.
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(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

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Q179 CBSE 2024
Q. 17 to 20 consists of two statements – Assertion (A) and Reason (R), answer these questions selecting the appropriate option given below :
Assertion (A): Receptors are usually located in our sense organs and perceive a particular stimulus.
Reason (R): Different sense organs have different receptors for detecting stimuli.
1. (a)Both (A) and (R) are true and (R) is the correct explanation of (A).
2. (b)Both (A) and (R) are true and (R) is not correct explanation of (A).
3. (c)(A) is true, but (R) is false.
4. (d)(A) is false, but (R) is true.
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(a) Both (A) and (R) are true and (R) is the correct explanation of (A).

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Q180 CBSE 2024
1. (i)Write the significance of peripheral nervous system in human beings.
2. (ii)How is human brain protected from mechanical injuries and shocks ?
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The peripheral nervous system links the central nervous system with the body; the brain is protected by the cranium and fluid-filled membranes.
(i) The peripheral nervous system, made of the cranial nerves arising from the brain and the spinal nerves arising from the spinal cord, links the central nervous system with all the other parts of the body. It carries information from the receptors in the sense organs to the brain and spinal cord, and carries their messages to the effectors, the muscles and glands. (ii) The brain sits inside a bony box, the cranium (skull), which protects it from mechanical injury; inside this box it is contained in a fluid-filled balloon (membranes holding cerebrospinal fluid) that absorbs shocks.

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