Question

15.
touch - me - nots (mimosa pudica) are plants that rapidly respond to touch. by affecting the turgor pressure in their cells, these plants can cause their leaves to quickly droop allowing them to defend themselves from herbivorous animals. this rapid response to touch is known as -
options:
thigmonasty
phototropism
photonasty
gravitropism

Explanation:

The question describes Mimosa pudica's rapid leaf drooping in response to touch. Thigmonasty is the non-directional plant response to touch. Phototropism is growth toward light, photoperiodism is response to day length, and gravitropism is response to gravity. Only thigmonasty matches the touch-induced reaction.

Answer:

thigmonasty