Question

Consider the following phenomena:
1. Closing of leaves by touch-me-not plant on touching its leaves.
2. Growth of plant towards light.
Which of them is a response to a 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 are directional movements i.e., either towards or away from stimulus. Both these movements are response to stimuli.