--- title: "NCERT Solutions Class 10 Science Ch 6 Control and Coordination" url: https://www.swavid.com/science/class/10/chapter/control-and-coordination/ncert-solutions dateModified: 2026-10-07T16:44:34+00:00 --- # NCERT Solutions Class 10 Science Ch 6 Control and Coordination This chapter's questions cover the mechanisms of control and coordination in animals and plants through the nervous system, reflex actions, the human brain, plant movements, and hormonal regulation. Free PDF (11 pages): https://www.swavid.com/api/seo/pdf/ncert/science/class-10/swavid-ncert-solutions-class-10-science-chapter-6-control-and-coordination-46cb81cd81.pdf ## QUESTIONS ### Question 1 *3 marks · Short answer* What is the difference between a reflex action and walking? **Solution** 1. A reflex action is a rapid, automatic, and involuntary response to a stimulus that does not involve conscious thinking. 2. Walking is a voluntary action that is under conscious control and is coordinated by the cerebellum in the hind-brain. 3. Reflex actions are controlled mainly by the spinal cord, whereas voluntary actions like walking require signals originating from the brain. **Answer:** Reflex action is an involuntary, rapid response controlled by the spinal cord, whereas walking is a voluntary action coordinated by the brain and cerebellum. > Common mistake: Confusing reflex actions with involuntary actions controlled by the brain or mixing up voluntary and involuntary controls. ### Question 2 *3 marks · Short answer* What happens at the synapse between two neurons? **Solution** 1. When an electrical impulse reaches the end of the axon of a neuron, it sets off the release of specific chemicals into the gap or synapse. 2. These chemicals cross the synapse and reach the dendritic tip of the next neuron. 3. The chemicals start a similar electrical impulse in the dendrite of the next neuron for onward transmission. **Answer:** At the synapse, the electrical impulse sets off the release of chemicals that cross the gap and start a new electrical impulse in the next neuron. > Common mistake: Stating that electrical impulses directly jump across the synaptic gap without chemical intermediaries. ### Question 3 *2 marks · Very short answer* Which part of the brain maintains posture and equilibrium of the body? **Solution** 1. The cerebellum, which is a part of the hind-brain, is responsible for maintaining posture and equilibrium of the body. 2. It also ensures precision during voluntary actions. **Answer:** The cerebellum in the hind-brain maintains the posture and equilibrium of the body. > Common mistake: Confusing the cerebellum with the cerebrum or medulla. ### Question 4 *3 marks · Short answer* How do we detect the smell of an agarbatti (incense stick)? **Solution** 1. The smell of an agarbatti (incense stick) is detected by olfactory receptors present in our nose, specifically in the nasal chambers. 2. The olfactory receptors receive the chemical particles of the scent, which trigger a chemical reaction that creates an electrical impulse. 3. This electrical impulse is transmitted via sensory nerves to the fore-brain, where the information is interpreted as smell. **Answer:** Olfactory receptors in the nose detect the scent particles, generate an electrical impulse, and send it to the fore-brain for interpretation. > Common mistake: Forgetting to mention gustatory versus olfactory receptors or omitting the role of the fore-brain. ### Question 5 *3 marks · Short answer* What is the role of the brain in reflex action? **Solution** 1. Reflex arcs are formed in the spinal cord itself for quick responses without involving conscious thinking. 2. However, the information input regarding the stimulus also goes on to reach the brain. 3. The brain receives these signals and records the reflex event, enabling awareness of the response even though it did not direct the immediate action. **Answer:** While reflex arcs are formed in the spinal cord for immediate action, the brain receives the input information to record and process the event. > Common mistake: Stating that the brain has no role or involvement in reflex actions. ## QUESTIONS ### Question 1 *2 marks · Very short answer* What are plant hormones? **Solution** 1. Plant hormones are chemical compounds synthesised by plants at places away from where they act. 2. They help to coordinate growth, development, and responses to the environment by simply diffusing to the area of action. **Answer:** Plant hormones are chemical substances produced by plants that help coordinate growth, development, and environmental responses. > Common mistake: Confusing plant hormones with animal hormones or thinking they are conducted through a nervous system. ### Question 2 *3 marks · Short answer* How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light? **Solution** 1. The movement of leaves of the sensitive plant is immediate in response to touch and independent of growth, occurring by changing the amount of water in cells. 2. The movement of a shoot towards light is a directional growth movement (phototropism) which is slow and caused by the unequal distribution of auxin. 3. Thus, the sensitive plant movement is rapid and non-growth-related, whereas the shoot movement is slow and growth-related. **Answer:** Movement in the sensitive plant is rapid, non-growth-related, and caused by water level changes, while shoot movement towards light is slow and caused by directional growth. > Common mistake: Forgetting to mention that one involves growth and the other does not. ### Question 3 *2 marks · Very short answer* Give an example of a plant hormone that promotes growth. **Solution** 1. Auxin, gibberellins, and cytokinins are examples of plant hormones that promote growth. 2. For instance, auxin helps in the growth of stems and cell elongation. **Answer:** Auxin (or Gibberellin / Cytokinin). > Common mistake: Writing abscisic acid, which is a growth inhibitor. ### Question 4 *3 marks · Short answer* How do auxins promote the growth of a tendril around a support? **Solution** 1. When tendrils come in contact with any support, the part of the tendril in contact with the object does not grow as rapidly as the part away from the object. 2. Auxin diffuses towards the part away from the support, stimulating those cells to grow longer. 3. This unequal growth causes the tendril to circle around the object and cling to it. **Answer:** Auxin stimulates rapid cell growth on the side of the tendril away from the support, causing it to circle around and cling to the object. > Common mistake: Stating that growth is faster on the side touching the support instead of the side away from it. ### Question 5 *5 marks · Long answer* Design an experiment to demonstrate hydrotropism. **Solution** 1. Take a porous pot and plant a germinating seed in a trough filled with soil. 2. Water the soil occasionally, but keep a small amount of water inside the porous pot near the seedling. 3. After a few days, carefully remove the roots from the soil and observe their direction of growth. 4. Observation: The roots bend towards the porous pot containing water, showing positive hydrotropism. 5. Conclusion: Roots grow towards water, demonstrating that hydrotropism is a directional growth movement in response to water stimulus. **Answer:** Hydrotropism can be demonstrated by growing seeds near a porous pot of water and observing that roots bend towards the moisture source. > Common mistake: Not mentioning the setup involving a moisture source like a porous pot. ## QUESTIONS ### Question 1 *3 marks · Short answer* How does chemical coordination take place in animals? **Solution** 1. Animals use chemical communication through hormones released by endocrine glands. 2. These hormones are secreted directly into the blood and carried to target organs or specific tissues throughout the body. 3. The target tissues respond to these chemical signals to bring about necessary control and coordination. **Answer:** Chemical coordination in animals takes place through hormones secreted by endocrine glands directly into the blood, which transport them to specific target organs. > Common mistake: Stating that hormones are transported via nerves instead of blood. ### Question 2 *3 marks · Short answer* Why is the use of iodised salt advisable? **Solution** 1. Iodine is essential for the thyroid gland to make the thyroxin hormone. 2. Thyroxin regulates carbohydrate, protein and fat metabolism in the body to provide the best balance for growth. 3. Deficiency of iodine in the diet can lead to a disease called goitre, characterised by a swollen neck. **Answer:** Iodised salt is advisable because iodine is essential for the thyroid gland to synthesize thyroxin, which regulates body metabolism and growth, preventing goitre. > Common mistake: Forgetting to mention the role of thyroxin in metabolism and growth. ### Question 3 *3 marks · Short answer* How does our body respond when adrenaline is secreted into the blood? **Solution** 1. Adrenaline is secreted directly into the blood and carried to target organs like the heart. 2. The heart beats faster to supply more oxygen to muscles, while breathing rate increases due to contractions of the diaphragm and rib muscles. 3. Blood is diverted from the digestive system and skin to skeletal muscles by the contraction of muscles around small arteries, preparing the body to deal with scary or emergency situations. **Answer:** When adrenaline is secreted, the heart beats faster, breathing rate increases, and blood is diverted to skeletal muscles, preparing the body for fighting or running away. > Common mistake: Not mentioning the redistribution of blood flow to skeletal muscles. ### Question 4 *3 marks · Short answer* Why are some patients of diabetes treated by giving injections of insulin? **Solution** 1. Insulin is a hormone produced by the pancreas that helps in regulating blood sugar levels in the body. 2. In patients with diabetes, insulin is either not secreted in proper amounts or not produced at all, causing blood sugar levels to rise. 3. Taking injections of insulin helps regulate and lower these high blood sugar levels, preventing harmful effects. **Answer:** Some patients of diabetes are treated with insulin injections because their body lacks sufficient insulin production, and insulin helps regulate blood sugar levels. > Common mistake: Confusing the source gland of insulin or its primary function in metabolism. ## EXERCISES ### Question 1 *1 mark · MCQ* Which of the following is a plant hormone? - Insulin - Thyroxin - Oestrogen - Cytokinin. **Solution** 1. Cytokinin is a plant hormone that promotes cell division, whereas insulin, thyroxin, and oestrogen are animal hormones. **Answer:** (d) Cytokinin. > Common mistake: Confusing plant hormones with animal hormones like insulin or thyroxin. ### Question 2 *1 mark · MCQ* The gap between two neurons is called a - dendrite. - synapse. - axon. - impulse. **Solution** 1. The gap between the end of the axon of one neuron and the dendrite of the next neuron is called a synapse. **Answer:** (b) synapse. > Common mistake: Confusing synapse with axon or dendrite. ### Question 3 *1 mark · MCQ* The brain is responsible for - thinking. - regulating the heart beat. - balancing the body. - all of the above. **Solution** 1. The brain is responsible for thinking (fore-brain), regulating heartbeat (medulla in hind-brain), and balancing the body (cerebellum). **Answer:** (d) all of the above. > Common mistake: Choosing only one function like thinking or balancing while ignoring others. ### Question 4 *3 marks · Short answer* What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise? **Solution** 1. Receptors are specialised tips of nerve cells that detect all information and changes in our environment, usually located in sense organs. 2. If receptors do not work properly, they fail to detect environmental signals such as heat, taste, or smell. 3. As a result, our body will not respond in time to dangerous situations, making us vulnerable to harm or injury. **Answer:** Receptors detect environmental information; if they fail, the body cannot perceive stimuli or respond to dangerous situations. > Common mistake: Forgetting to mention the consequences of receptors failing to work. ### Question 5 *5 marks · Long answer* Draw the structure of a neuron and explain its function. **Solution** 1. Diagram: Draw the structure of a neuron showing dendrite, cell body (cyton), nucleus, axon, and nerve ending as in Fig. 6.1 (a). 2. Information from the environment is acquired at the dendritic tip of a nerve cell, setting off a chemical reaction that creates an electrical impulse. 3. This electrical impulse travels from the dendrite to the cell body and then along the axon to its nerve ending. 4. At the end of the axon, the impulse triggers the release of chemicals that cross the synapse to reach the next neuron or muscle cell. **Answer:** A neuron consists of dendrites, cell body, and axon, and is specialised for conducting information via electrical impulses. > Common mistake: Not labeling the parts correctly in the diagram. ### Question 6 *3 marks · Short answer* How does phototropism occur in plants? **Solution** 1. Phototropism is the directional movement of plant parts in response to light, such as shoots bending towards light. 2. When growing plants detect light, a hormone called auxin is synthesised at the shoot tip and diffuses towards the shady side of the shoot. 3. This higher concentration of auxin stimulates the cells on the shady side to grow longer than those on the illuminated side, making the plant appear to bend towards light. **Answer:** Phototropism occurs due to the unequal distribution of auxin hormone, causing cells on the shady side to grow longer. > Common mistake: Stating that auxin grows faster on the side facing light instead of the shady side. ### Question 7 *3 marks · Short answer* Which signals will get disrupted in case of a spinal cord injury? **Solution** 1. Reflex arcs are formed in the spinal cord itself, so reflex actions originating from areas below the injury would be disrupted. 2. Signals coming from the receptors and going to the brain, as well as instructions coming from the brain to various body parts, pass through the spinal cord. 3. Therefore, spinal cord injury would disrupt both reflex responses and communication between the brain and the rest of the body. **Answer:** Spinal cord injury disrupts reflex actions for lower parts of the body and blocks communication signals between the brain and the rest of the body. > Common mistake: Forgetting that the spinal cord also acts as a highway for signals travelling between the brain and the rest of the body. ### Question 8 *3 marks · Short answer* How does chemical coordination occur in plants? **Solution** 1. Plants use plant hormones, also known as phytohormones, for chemical coordination. 2. These chemical compounds are synthesised at places away from where they act and simply diffuse to the area of action. 3. Different plant hormones help to coordinate growth, development, and responses to the environment, such as auxins promoting shoot growth and abscisic acid inhibiting growth. **Answer:** Chemical coordination in plants occurs through plant hormones that are synthesised at one location and diffuse to other areas to regulate growth and responses. > Common mistake: Confusing plant hormones with animal hormones or nervous signals. ### Question 9 *3 marks · Short answer* What is the need for a system of control and coordination in an organism? **Solution** 1. Multicellular organisms have complex bodies made of specialized tissues and organ systems that must function in a synchronized manner. 2. Living organisms constantly face changes in their environment and need to respond to them correctly and quickly for survival. 3. A system of control and coordination is necessary to maintain overall body organization, integrate various activities, and protect the organism from dangers. **Answer:** Control and coordination systems are needed to integrate diverse body functions, respond appropriately to environmental changes, and ensure survival. > Common mistake: Writing only about responses to danger without mentioning internal body maintenance and integration. ### Question 10 *3 marks · Short answer* How are involuntary actions and reflex actions different from each other? **Solution** 1. Involuntary actions are controlled by the mid-brain and hind-brain, such as the regulation of heart beat, breathing, and blood pressure, whereas reflex actions are sudden responses often controlled by the spinal cord. 2. Involuntary actions do not necessarily involve a specific external stimulus and happen continuously, while reflex actions are immediate responses to specific environmental stimuli. 3. Involuntary actions represent ongoing internal regulation, whereas reflex actions act as efficient protective mechanisms for quick responses. **Answer:** Involuntary actions are continuous internal processes controlled by the brain, whereas reflex actions are sudden, rapid responses to external stimuli managed primarily by the spinal cord. > Common mistake: Treating involuntary actions and reflex actions as identical because both occur without conscious thinking. ### Question 11 *5 marks · Long answer* Compare and contrast nervous and hormonal mechanisms for control and coordination in animals. **Solution** 1. Nervous system transmission uses electrical impulses along nerve cells, whereas the endocrine system uses chemical compounds called hormones transported through blood. 2. Nerve impulses are very rapid in their action, whereas hormonal responses are generally slower. 3. Nervous pathways are specific and reach only those cells connected by nervous tissue, whereas hormones reach all cells of the body via the bloodstream. 4. Electrical impulses cannot be generated continuously by a cell as it needs time to reset, whereas chemical communication can be carried out steadily and persistently. 5. Both systems complement each other to provide complete control and coordination in animal bodies. **Answer:** Nervous mechanisms use fast electrical impulses along specific nerve connections, while hormonal mechanisms use slower chemical signals carried by blood to reach all body cells. > Common mistake: Failing to cover both similarities and differences between the two systems. ### Question 12 *3 marks · Short answer* What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs? **Solution** 1. Movement in a sensitive plant like Mimosa is independent of growth and occurs due to changes in the amount of water in plant cells, causing them to swell or shrink. 2. Movement in our legs is a voluntary action brought about by specialized animal muscle tissue that changes shape using special proteins in response to nervous electrical impulses. 3. Plant movements rely on electrical-chemical means and water-based cell shape changes without a nervous system, whereas leg movements use complex nervous pathways and muscular contractions. **Answer:** Sensitive plant movement is growth-independent and caused by water-level changes in cells, while leg movement uses nervous impulses and specialized muscle proteins. > Common mistake: Stating that plants have muscles to move their leaves. ## Frequently asked questions ### How many questions and exercises are there in the NCERT Solutions for Class 10 Science Chapter 6? The NCERT textbook for the 2026-27 session includes 12 exercises alongside specific question sets covering topics like receptors, nervous system structure, and plant hormones. You can find SwaVid's free PDF and step-by-step solutions for all these questions on this page only. ### Which major topics are covered in the questions for this chapter? The questions cover essential concepts such as the detection of smell by olfactory receptors, differences between reflex action and walking, events at the synapse, and the function of the cerebellum. Other covered topics include auxin action in tendrils, plant growth hormones, the action of adrenaline, and the role of insulin in diabetes. ### What are the hardest question types in these solutions and how should I approach them? Long answer and short answer questions involving complex processes like chemical coordination in animals and plant movements are often considered the hardest. To approach them, break down the physiological steps logically and use SwaVid's free PDF and step-by-step solutions available on this page only to understand the core mechanism. ### How can I write answers to score full marks in Class 10 Science Chapter 6 examinations? To secure full marks, write precise answers using scientific terminology and reference specific NCERT concepts like the role of the brain in reflex action or the importance of iodised salt. Structuring your answers with clear points helps examiners award maximum marks. ### Is the free PDF for these NCERT solutions available for download? Yes, complete solutions mapped to the 2026-27 session are easily accessible. You can access SwaVid's free PDF and step-by-step solutions on this page only to prepare effectively for your exams. ## Related pages - [Control and Coordination: CBSE previous year questions](https://www.swavid.com/cbse/class-10/science/pyq/control-and-coordination) - [Class 10 Science chapters](https://www.swavid.com/science/class/10) 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