Reproduction, I am pretty sure
Hope this help
By warming up your muscles (I am assuming you mean by stretching and doing jumping jacks and such, not sitting yourself in front of a heater...) you will have a better overall workout. Your muscles will be ready to work and you will not tire as fast. Also, your muscles will feel better the next day because you got them ready to work out.
Answer:
D. Autotrophs
Explanation:
Because the sun's energy is used in plants (Autotrophs) for photosynthesis.