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 7 of 15

Q121 CBSE 2026
Read the following passage and answer the questions that follow : In many animals including humans, adrenaline hormone prepares for scary situation. The target organs on which it acts include the heart. The blood to the digestive system and skin is reduced, but the heart beats faster and breathing rate also increases. All these responses together enable the animal body to deal with such scary situation.
1. (a)(i)Name the gland that secretes adrenaline hormone. How does it enable the animal body to deal with a scary situation ?[2]
2. (a)(ii)OR : Why is the blood to the digestive system and skin reduced ?[2]
3. (b)Why is it important for us to have iodised salt in our diet ?[1]
4. (c)Why does a doctor advise some persons to take less sugar in their diet ?[1]
Show answer

Adrenal glands secrete adrenaline to prepare the body for danger; iodine is needed for thyroxine; diabetics must cut sugar because of low insulin.
(a)(i) The **adrenal glands**, one above each kidney, secrete adrenaline. It is poured straight into the blood and carried to its target organs. It makes the heart beat faster, so more oxygen-rich blood reaches the muscles; it makes the smooth muscles around the small arteries of the digestive system and skin contract, so that blood is diverted from them to the skeletal muscles; and the breathing rate also increases, because of the contractions of the diaphragm and the rib muscles, so more oxygen is taken into the blood. Together these changes supply the skeletal muscles with the extra oxygen and glucose they need, and so enable the body to deal with the scary situation. OR (a)(ii) Because the smooth muscles around the small arteries supplying the digestive system and the skin contract and narrow them. Digestion and heat loss from the skin can wait in an emergency, so the blood saved there is diverted to the skeletal muscles, which need more oxygen and glucose to act quickly. (b) Iodine is needed by the thyroid gland to make the hormone thyroxine, which regulates carbohydrate, protein and fat metabolism. Too little iodine in the diet means too little thyroxine, and the person suffers from goitre, with a swollen neck; iodised salt supplies the iodine. (c) Because such persons are diabetic: their pancreas does not secrete enough insulin, the hormone that lowers blood sugar, so the sugar they eat keeps the blood sugar level high. Taking less sugar keeps that level within what their weakened control can manage.

Step-by-step solution →
Q122 CBSE 2026
1. (i)What are the limitations of electrical impulses in multicellular organisms ?
2. (ii)(I) In a ‘Touch-me-not’ plant, movement is seen on touch. Compare it with that of animals. (II) Name the type of movement shown by the growth of pollen tube towards an ovule.
Show answer

Impulses reach only connected cells and need resetting; touch-me-not folds by water loss while animals use muscle; pollen tube growth is chemotropism.
(i) Limitations of electrical impulses: (1) they reach only those cells that are connected by nervous tissue, not each and every cell of the body; (2) once a nerve cell has generated and transmitted an impulse it must reset its mechanism before it can send another, so impulses cannot be created and transmitted continuously; (3) the impulse is short-lived, so it cannot by itself bring about a lasting effect such as growth. Multicellular organisms therefore also use chemical communication, which is slower but reaches every cell and lasts longer. (ii)(I) In the Touch-me-not plant there is no nervous tissue and no muscle. The touch is passed from cell to cell as an electrochemical signal, and the cells in the swelling at the base of the leaflet lose water, become flaccid and shrink, so the leaflet folds; the movement is independent of growth and happens at a point different from the point of touch (the swelling at the base of the leaflet), which is why the information of touch has to be passed on from cell to cell. In animals the touch is detected by a receptor, carried along a sensory neuron to the spinal cord or brain and out along a motor neuron, and a muscle contracts; animal cells change shape by means of special proteins in muscle cells, not by changing their water content. Both are rapid responses carried by an electrical signal, but the plant uses no nerves, no muscle and no central nervous system. (ii)(II) Chemotropism.

Step-by-step solution →
Q123 CBSE 2026
1. (i)Reflex arcs have evolved in animals because the thinking process of the brain is not fast enough for all situations. Draw a flow chart showing the path of a reflex arc.
2. (ii)Given below are some actions/activities. Identify the part of brain involved in controlling them : (I) Taking a walk in the garden (II) Dancing (III) Blood pressure
Show answer

The reflex message turns round at the spinal cord; walking uses the cerebrum, dancing the cerebellum, blood pressure the medulla.
(i) Path of a reflex arc: Stimulus (for example, a hot object) $\to$ Receptor (in the skin) $\to$ Sensory neuron $\to$ Spinal cord (relay neuron) $\to$ Motor neuron $\to$ Effector (muscle of the arm) $\to$ Response (the hand is withdrawn). The message is switched across in the spinal cord and not in the brain, which is what makes the response immediate. (ii)(I) Taking a walk in the garden: fore-brain (cerebrum), which directs voluntary movement of the leg muscles; the cerebellum helps by maintaining posture and balance. (ii)(II) Dancing: cerebellum (hind-brain), which is responsible for the precision of voluntary actions and for maintaining the posture and balance of the body. (ii)(III) Blood pressure: medulla (hind-brain), which controls involuntary actions.

Step-by-step solution →
Q124 CBSE 2025
The part of the brain which maintains the posture and balance of the body is :
1. (a)Pons
2. (b)Cerebrum
3. (c)Cerebellum
4. (d)Medulla
Show answer

(c) Cerebellum

Step-by-step solution →
Q125 CBSE 2025
The part of the hindbrain present immediately above the medulla is :
1. (a)Cerebellum
2. (b)Pons
3. (c)Cerebrum
4. (d)Spinal cord
Show answer

(b) Pons

Step-by-step solution →
Q126 CBSE 2025
The part of the hind-brain controlling involuntary actions such as salivation and vomiting in humans is :
1. (a)Cerebellum
2. (b)Cerebrum
3. (c)Pons
4. (d)Medulla
Show answer

(d) Medulla

Step-by-step solution →
Q127 CBSE 2025
The growth of the pollen tubes towards ovules is an example of :
1. (a)Phototropism
2. (b)Hydrotropism
3. (c)Geotropism
4. (d)Chemotropism
Show answer

(d) Chemotropism

Step-by-step solution →
Q128 CBSE 2025
Observe the given figures A and B. When chhui-mui (sensitive) plant is touched, its leaves fold. This is due to :
Figure A and Figure B
1. (a)Hormonal effect
2. (b)Thermal effect
3. (c)Change in amount of water in cells
4. (d)Electromagnetic effect
Show answer

(c) Change in amount of water in cells

Step-by-step solution →
Q129 CBSE 2025
The plant hormone present in greater concentration in the areas of rapidly dividing cells is :
1. (a)Auxin
2. (b)Cytokinins
3. (c)Gibberellins
4. (d)Abscisic acid
Show answer

(b) Cytokinins

Step-by-step solution →
Q130 CBSE 2025
Application of Abscisic acid on plants promotes :
1. (a)Development of fruits
2. (b)Wilting of leaves
3. (c)Elongation of stem
4. (d)Formation of flowers
Show answer

(b) Wilting of leaves

Step-by-step solution →
Q131 CBSE 2025
Electrical impulse travels in a neuron from
1. (a)Nerve ending → Axon → Cell body → Dendrite
2. (b)Dendrite → Cell body → Axon → Nerve ending
3. (c)Cell body → Dendrite → Axon → Nerve ending
4. (d)Dendrite → Axon → Nerve ending → Cell body
Show answer

(b) Dendrite → Cell body → Axon → Nerve ending

Step-by-step solution →
Q132 CBSE 2025
The plant hormone whose concentration stimulates the cells to grow longer on the side of the shoot which is away from light is :
1. (a)Cytokinins
2. (b)Gibberellins
3. (c)Adrenaline
4. (d)Auxins
Show answer

(d) Auxins

Step-by-step solution →
Q133 CBSE 2025
Which among the following is not a neural action controlled by the part of human brain labelled 'X' in the figure above ?
1. (a)Salivation
2. (b)Hunger
3. (c)Vomiting
4. (d)Blood Pressure
Show answer

(b) Hunger

Step-by-step solution →
Q134 CBSE 2025
A pair of endocrine glands located in the human brain is
1. (a)Parathyroid and Pituitary
2. (b)Pineal and Thymus
3. (c)Hypothalamus and Thymus
4. (d)Hypothalamus and Pineal
Show answer

(d) Hypothalamus and Pineal

Step-by-step solution →
Q135 CBSE 2025
A voluntary action such as writing on a paper is controlled by the part of brain called
1. (a)Cerebrum
2. (b)Cerebellum
3. (c)Pons
4. (d)Medulla
Show answer

(a) Cerebrum

Step-by-step solution →
Q136 CBSE 2025
A gland which does not occur as a pair in the body of human beings is :
1. (a)Adrenal
2. (b)Ovary
3. (c)Pituitary
4. (d)Testis
Show answer

(c) Pituitary

Step-by-step solution →
Q137 CBSE 2025
The plant part/parts having greater concentration of cytokinins is/are
1. (a)fruits only
2. (b)leaves
3. (c)fruits and seeds
4. (d)seeds and leaves
Show answer

(c) fruits and seeds

Step-by-step solution →
Q138 CBSE 2025
The plant hormones promoting rapid cell division in seeds and wilting of leaves respectively are
1. (a)Auxins and Abscisic acid
2. (b)Cytokinins and Abscisic acid
3. (c)Gibberellins and Auxins
4. (d)Abscisic acid and Gibberellins
Show answer

(b) Cytokinins and Abscisic acid

Step-by-step solution →
Q139 CBSE 2025
Two statements are given below — 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) given below.
Assertion (A): In our actions of writing or talking, our nervous system communicates with the muscles.
Reason (R): Cranial nerves and spinal nerves form the peripheral nervous system.
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.
Show answer

(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

Step-by-step solution →
Q140 CBSE 2025
1. (a)How is brain protected in our body ?
2. (b)A doctor finds in one of his patients that he is not maintaining a proper posture and balance of his body. State the region of brain and also the part of brain which is responsible for it.
Show answer

A bony cranium, three meninges and cerebrospinal fluid protect the brain; the cerebellum of the hind-brain maintains posture and balance.
(a) The brain is protected by a bony box, the cranium of the skull; inside it the brain is covered by three membranes, the meninges, and it is contained in a fluid filled balloon of cerebrospinal fluid, which cushions it against shocks. (b) Region of the brain: the hind-brain. Part responsible: the cerebellum, which maintains posture and balance of the body.

Step-by-step solution →