Which of the following is an example of a positive feedback mechanism?

A gradient exists:

a. when heat is concentrated in one area of the body.

b. when more of a substance is located in one place than in another.

c. when there is higher pressure in one place than in another.

d. All of the above are correct.

e. None of the above are correct.

Which example most clearly describes a system maintained by homeostasis?

Which example below describes a system that is NOT able to maintain homeostasis?