Answer:
A(the first one)
Explanation:
Homeostasis maintains the constant internal conditions in an organism. It is important because cells function best with a limited range of conditions. ... All living things have body parts with different functions that help them survive.
C. 20 because 39-19 is 20 so there are 20 neutrons and the atomic number is the same as number of protons and electrons.
The answer is B, fossil fules