A change in an organism's surroundings that causes it to react is called

A. a response

B. energy

C. a stimulus

D. development

A stimulus is the change in an organism's surroundings that causes it to react (quickly).

Some examples of stimulus are:

When you touch a boiling pot, you pull your hand quickly.

When an object is falling or thrown towards you, you close your eyes and sometimes you move a side.

A change in a organism's surroundings that causes the organism to react is called a stimulus