Question

Consider the following phenomena:
1. Closing of leaves by touch-me-not plant on touching its leaves.
2.The growth of the plant towards the light.
Which of them is a response to stimulus?

• A. Only 1
• B. Only 2
• C. Both 1 & 2
• D. None

Answer 1

The correct option is C Both 1 & 2

Movement in touch-me-not plant is a non-directional movement, which means that the response is independent of the direction of the stimulus. Growth towards light, gravity or water is directional movements i.e., either towards or away from the stimulus. Both these movements are response to stimuli.