The answer is B. Speed up chemical reactions. Hope this helps.
c proteins .. most used cuz it provides energy and builds muscle
They contain high protein, starch and oil reserves that help in the early stages of growth and development in a plant.
I think so it is molecules
Due to a reduction in blood volume due to blood donation, the stroke volume will decrease. However, to compensate for this, your heart rate will increase so as to maintain your cardiac output. Cardiac output is stroke volume multiplied with heart rate.
Maintaining normal cardiac output is critical so the whole body receives enough nutrients and oxygen.