question_answer

(a) Write three main functions of the nervous system.

(b) In the absence of muscle cells, how do plant cells show movement?

Answer:

(a) Main functions of the nervous system:

(i) Coordinate the activities of the body.

(ii) Helps all other systems of the body to work together.

(iii) The nervous system receives information from the surroundings, processes it, interprets it and then responds accordingly.

(b) The movement in any part of a plant is usually a growth movement or change in shape of body parts.

(i) The movements of the plant part are usually caused by an unequal growth in its two regions by the action of plant hormones, under the influence of the stimuli like light, force of gravity, chemical substances, water, touch etc.

(ii) The change in shape occurs by changing the amount of water in the body part. Water causes swelling and shrinking which causes movement.