A. carbon uhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh duhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
Answer:
Enzymes serve as catalysts to many biological processes, and so they are not used up in reactions and they may be recovered and reused. However, in a laboratory setting, reactions involving enzymes can leave the enzyme unrecoverable. This process makes the enzyme at once less reactive but more stable.
C because oxygen was a byproduct of photosynthesis and proved to be EXTREMELY important in the atmosphere.