Choose the word that best completes each sentence.
The growth of a plant in response to stimulus is called a tropism
The growth of a plant in resposne to touch is called
The growth of a plant in response to light is called
THE

the cell theory states that all living things including animals, as well as plants, are made of cells.

the answer is :

all these collisions do one thing, and that thing is explained in the last option. when dusst, rocks and ice collide, they harden and form giant layers of rocks or hard ice.

d)   to harden materials to form different parts of earth’s layers

hope it ,

bioteacher101