10th Control and Co-ordination NCERT Solution

Answers to Science Questions

1. Which of the following is a plant hormone?

(a) Insulin

(b) Thyroxin

(c) Oestrogen

(d) Cytokinin.

Answer: (d) Cytokinin.

2. The gap between two neurons is called a

(a) dendrite.

(b) synapse.

(c) axon.

(d) impulse.

Answer: (b) synapse.

3. The brain is responsible for

(a) thinking.

(b) regulating the heart beat.

(c) balancing the body.

(d) all of the above.

Answer: (d) all of the above.

4. What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?

Answer: Receptors detect changes in the environment and send signals to the brain. If they don’t work properly, problems like inability to feel pain, temperature, or touch, and difficulty in responding to stimuli may arise.

5. Draw the structure of a neuron and explain its function.

Answer: [Imagine a neuron with a cell body, dendrites, axon, and synapse.] A neuron transmits electrical impulses: dendrites receive signals, the axon carries them away, and the synapse passes them to the next neuron, enabling communication in the nervous system.

6. How does phototropism occur in plants?

Answer: Phototropism occurs when plants grow toward light due to the hormone auxin, which accumulates on the shaded side, causing cells there to elongate and bend the plant toward the light.

7. Which signals will get disrupted in case of a spinal cord injury?

Answer: Signals related to movement, sensation, and reflex actions below the injury site will get disrupted.

8. How does chemical coordination occur in plants?

Answer: Chemical coordination in plants occurs through hormones like auxin and cytokinin, which regulate growth, development, and responses to environmental changes.

9. What is the need for a system of control and coordination in an organism?

Answer: A system of control and coordination is needed to respond to stimuli, maintain homeostasis, and ensure proper functioning of organs and systems.

10. How are involuntary actions and reflex actions different from each other?

Answer: Involuntary actions are automatic body functions (e.g., heartbeat) controlled by the autonomic nervous system, while reflex actions are rapid, unconscious responses (e.g., pulling hand from heat) to specific stimuli.

11. Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.

Answer: Nervous control is fast, using electrical impulses via neurons for immediate responses, while hormonal control is slower, using chemicals (hormones) via blood for long-term effects. Both regulate body functions but differ in speed and duration.

12. What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?

Answer: Sensitive plant movement is a rapid, involuntary response due to changes in turgor pressure when touched, while leg movement is a voluntary action controlled by the brain and muscles via the nervous system.