Question

Choose the correct statements from the following options.

• A. Nastic movements are directed movements.
• B. Tropic movements are non directed movements.
• C. Thigmonasty is a nastic movement which occurs in response to touch.
• D. Geotropism is a tropic movement which occurs in response to gravity.

Answer 1

Answer: (C), (D)

Geotropism is a tropic movement which occurs in response to gravity.

There are 2 types of movements in plants- tropic and nastic movements. Tropic movements are directed movements which occur in response to external stimuli. Phototropism, geotropism, thigmotropism and chemotropism are examples of tropic movements which occur in response to light, gravity, touch and chemicals respectively.
Nastic movements are non-directed movements which occur in response to external stimuli. Photonasty, thigmonasty and thermonasty are examples of nastic movements which occurs in response to light, touch and temperature respectively.