Question

Movements of hair in Drosera is

• A. Photonastic
• B. Thermonastic
• C. Thigmonastic
• D. Seismonastic

Answer 1

Answer: (C)

Thigmonastic

Any nastic movement in response to touch or contact stimulus is known as thigmonasty. The tentacles of Drosera leaves curve on coming with any insects and thus, the movement is categorised as thigmonasty which makes option C correct. Any nastic movements caused in response to sunlight or temperature stimuli are known as photonastic and thermonastic movements respectively. This makes options A and B incorrect. Nastic movements in response to any mechanical shock, such as blow, shaking or pressure, are known as seismonastic movements. This makes option D incorrect. Correct answer is C.