The chemical substance P is made and secreted by the meristematic tissue at the tip of stem (or shoot) of a plant. The chemical substance P is responsible for a phenomenon Q in plants in which the stem bends towards a source of light. The same chemical substance P has an opposite effect on the root of a plant. It causes the root of a plant to bend away from the source of light in a process called R. Now, answer the following questions:
1. What is the chemical substance P ?
(i) Auxin
(ii) Abscisic acid
2. State whether P prefers to remain in the sunlit side of a stem or in shade.
(i) In sunlit area
(ii) Abscisic acid
3. What is the name of process Q?
(i) Positive phototropism
(ii) Negative phototropism
4. What is the name of process R?
(i) Positive phototropism
(ii) Negative phototropism
5. What is the general name of chemical substances like P ?
(i) Plant hormones
(ii) Plant ketones
