What is the stimulus in:
(a) phototropism?
(b) geotropism?
(c) chemotropism?
(d) hydrotropism?
(e) thigmotropism?
(a) Light is the stimulus in phototropism.
(b) Gravity is the stimulus in geotropism.
(c) Chemical is the stimulus in chemotropism.
(d) Water is the stimulus in hydrotropism.
(e) Touch is the stimulus in thigmotropism.