Energy used to fuel biological processes comes from the breakdown of .
A.
Carbohydrates
B.
Fats
C.
Proteins
D.
ATP

D. ATP

Explanation: chemical energy is stored in the bonds of adenosine triphosphate. muscle contraction work breaks the phosphate bonds producing energy and other byproducts.

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.