Answer:
A. Respiration
Explanation:
The process in which oxygen atoms are made available to the cell of animals is called cell respiration. In cell respiration the food molecules undergo process which is called food oxidization, that make it available to be absorbed by the animal cell.
The fossil record provides evidence of Earth’s changes over time. It's a record keeper of the Earth'd changes over time.
The answer is b. The ability of all living things to maintain a relatively stable internal environment
