A, O2 has to be a reactant for combustion to burn
Answer:
the first one to the third box
the second one to the fourth box
the third one to second box
and the fourth one to the first box
Explanation:
The Krebs cycle uses acetyl CoA as a reactant.
The nervous system sends signals to the muscles to shiver when our body temperature begins to drop to a lower than normal temperature. the slight movement of the muscles will work to bring temperature back to homeostasis
Increase at the temperature