Question

While conducting experiments to study the effect of various stimuli on the plants, it was observed that the roots of a plant X grow and bend towards two stimuli A and B but bend away from a third stimulus C. The stem of the plant X, however, bends away from stimuli A and B but bends towards the stimulus C. The stimulus B is known to act on the roots due to too much weight of the earth. Keeping these points in mind, answer the following question:

1. What could stimulus A be?
2. Name the stimulus B.
3. What could stimulus C be?
4. The branches of a fallen tree in a forest grow straight up in response to two stimuli. What could be these two stimuli out of A, B and C? Also name these two stimuli.

Answer 1

1. The stimulus A is water.
2. The stimulus B is gravity.
3. The stimulus C is light.
4. The two stimuli responsible for the straight growth of the branches of a fallen tree are B and C, i.e., gravity and light, respectively.