--- title: "Control and Coordination: CBSE Class 10 Science previous year questions" url: https://www.swavid.com/cbse/class-10/science/pyq/control-and-coordination --- # Control and Coordination: CBSE Class 10 Science previous year questions 10 questions from CBSE Class 10 board papers, newest first, each with full working. ## CBSE Class 10 Science Question Paper 2026 (Set 31/1/1) with Solutions ### Question 4 *1 mark · MCQ* Human brain has various parts or regions that help in different actions, responses and coordination. From the following, identify the part responsible for precision of voluntary actions : - Cerebrum - Cerebellum - Medulla - Pons **Solution** 1. The cerebellum is the part of the hindbrain responsible for maintaining posture, balance, and the precision of voluntary actions. 2. Cerebrum is for thinking, and medulla controls involuntary actions. **Answer:** (b) Cerebellum > Common mistake: Confusing cerebellum with cerebrum. ### Question 8 *1 mark · Assertion and reason* Assertion (A) : Reflex actions do not involve thinking. Reason (R) : Most reflex actions are controlled by the spinal cord. - Both, Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A). - Both, Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A). - Assertion (A) is true, but Reason (R) is false. - Assertion (A) is false, but Reason (R) is true. **Solution** 1. Reflex actions are sudden, involuntary responses to external stimuli that do not involve conscious thought. 2. Most reflex actions are mediated through the spinal cord for a quick response. **Answer:** Both, Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A). > Common mistake: Thinking that the reason does not explain the assertion because thinking happens in the brain. ## CBSE Class 10 Science Question Paper 2025 (Set 31/1/1) with Solutions ### Question 9 *1 mark · MCQ* The plant hormone whose concentration stimulates the cells to grow longer on the side of the shoot which is away from light is : - Cytokinins - Gibberellins - Adrenaline - Auxins **Solution** 1. Auxin is the plant hormone that synthesizes at the shoot tip and helps the cells to grow longer. 2. When light comes from one side, auxin diffuses towards the shady side of the shoot, stimulating greater cell elongation on that side. **Answer:** (d) Auxins > Common mistake: Confusing auxins with cytokinins or gibberellins. ### Question 29 *3 marks · Short answer* Plants have neither a nervous system nor muscles, even then they respond to stimuli. For example, the leaves of chhui-mui (touch-me-not) plant when touched begin to fold up and droop. (a) How is the information communicated in "touch-me-not" plants ? (b) What enables the plant cells to bring out the observable response ? (c) Differentiate the movement mentioned above from the movement of tendrils in a pea plant. **Part a** 1. Plants use electrical-chemical means to transmit information from one cell to another. Answer a: Information is communicated through electrical-chemical signals across plant cells. **Part b** 1. Plant cells change their shape by changing the amount of water in them, resulting in swelling or shrinking. Answer b: Changes in cellular water content enable plant cells to alter their shape and bring about an observable response. **Part c** 1. The movement of touch-me-not leaves is a nastic movement independent of growth and direction, whereas the movement of tendrils in a pea plant is a directional growth movement (thigmotropism). Answer c: Leaf folding is non-directional and independent of growth, while tendril movement is directional and growth-dependent. **Answer:** Plants communicate via electrical-chemical signals, bring about response by changing water content in cells, and show nastic movements unlike directional growth movements in tendrils. > Common mistake: Confusing nastic movements with tropic movements. ## CBSE Class 10 Science Question Paper 2024 (Set 31/1/1) with Solutions ### Question 10 *1 mark · MCQ* In a nerve cell, the site where the electrical impulse is converted into a chemical signal is known as : - Axon - Dendrites - Neuromuscular junction - Cell body **Solution** 1. At the end of the axon, the electrical impulse sets off the release of some chemicals at the nerve ending. 2. These chemicals cross the synapse (neuromuscular junction or synapse between neurons) and start a similar electrical impulse in a dendrite of the next neurone. **Answer:** (c) Neuromuscular junction > Common mistake: Confusing the axon terminal/synapse with dendrites. ### Question 23 *2 marks · Very short answer* How is the movement of leaves of a sensitive plant different from the downward movement of the roots ? **Solution** 1. The movement of leaves of a sensitive plant (such as Mimosa pudica) is a nastic movement, which is non-directional, rapid, and caused by changes in water content (turgor pressure). 2. The downward movement of roots is a tropic movement (gravitropism), which is a slow, directional growth movement in response to gravity. **Answer:** Sensitive plant movement is rapid, non-directional and turgor-based, whereas root movement is slow, directional and growth-based. > Common mistake: Not mentioning that root movement is a growth movement while touch-me-not plant movement is not a growth movement. ### Question 23 (OR) *2 marks · Very short answer* There is a hormone which regulates carbohydrate, protein and fat metabolism in our body. Name the hormone and the gland which secretes it. Why is it important for us to have iodised salt in our diet? **Solution** 1. The hormone is thyroxine and it is secreted by the thyroid gland. 2. Iodine is essential for the synthesis of thyroxine hormone by the thyroid gland. 3. Iodised salt is important to prevent deficiency diseases like goitre. **Answer:** Thyroxine, secreted by the thyroid gland; iodine is needed for its synthesis. > Common mistake: Forgetting to mention the thyroid gland or the role of iodine in thyroxine synthesis. ### Question 30 *3 marks · Short answer* Define reflex action. With the help of a flow chart show the path of a reflex action such as sneezing. **Solution** 1. A reflex action is a rapid, automatic response to a stimulus which is controlled by the spinal cord without the conscious will of the brain. 2. Stimulus (Irritant in nasal cavity) $\to$ Sensory nerve / Receptor $\to$ Spinal cord (CNS) $\to$ Motor neuron $\to$ Effector (Respiratory muscles / Diaphragm) $\to$ Response (Sneezing). **Answer:** Reflex action is a rapid, automatic response to a stimulus. Flow chart: Stimulus $\to$ Receptor $\to$ Sensory Neuron $\to$ Spinal Cord $\to$ Motor Neuron $\to$ Effector $\to$ Response. > Common mistake: Forgetting to include the spinal cord or mixing up the order of sensory and motor neurons in the reflex arc. ## CBSE Class 10 Science Question Paper 2023 (Set 31/1/1) with Solutions ### Question 11 *1 mark · MCQ* Select from the following the correct statement about tropic movement in plants : - It is due to stimulus of touch and temperature. - It does not depend upon the direction of stimulus received. - It is observed only in roots and not in stems. - It is a growth related movement. **Solution** 1. Tropic movements are directional growth movements that occur in response to an external stimulus. 2. Since they involve cell elongation or growth, they are growth-related movements dependent on the direction of the stimulus. **Answer:** (d) It is a growth related movement. > Common mistake: Confusing tropic movements with nastic movements which are non-directional. ### Question 22 *2 marks · Very short answer* (a) Write the role of insulin in regulating blood sugar levels in human body. Mention the disease caused due to it. (b) How is the timing and the amount of release of insulin in the blood regulated? **Part (a)** 1. Insulin helps in regulating blood sugar levels by lowering excess glucose in the blood. 2. Deficiency of insulin causes a disease known as diabetes. Answer (a): Regulates blood sugar levels; deficiency causes diabetes. **Part (b)** 1. The timing and amount of insulin released are regulated by feedback mechanisms. 2. When blood sugar rises, insulin is secreted; as sugar levels fall, secretion reduces. Answer (b): Regulated by feedback mechanisms based on blood sugar levels. **Answer:** Insulin regulates blood sugar by lowering it, and its deficiency causes diabetes. The timing and amount of release are controlled by feedback mechanisms. > Common mistake: Writing diabetes mellitus as just diabetes without mentioning blood sugar regulation clearly. ## Related pages - [Control and Coordination: NCERT solutions](https://www.swavid.com/science/class/10/chapter/control-and-coordination/ncert-solutions) - [All CBSE Class 10 Science papers](https://www.swavid.com/cbse/class-10/science/previous-year-papers) Solutions written by SwaVid, a personal AI tutor for Class 6 to 10 Maths and Science. Practise this chapter free: https://www.swavid.com/start/student