In explaining the importance of a constant blood supply to the brain, the nurse would tell the student which? 

a. Energy is needed to maintain nerve membranes and cannot be produced without oxygen. 

b. Carbon dioxide must constantly be removed to maintain the proper pH. 

c. Little glucose is stored in nerve cells, so a constant supply is needed. 

d. The brain needs a constant supply of insulin and thyroid hormone. 

e. The brain swells easily and needs the blood supply to reduce swelling. 

f. Circulating aldosterone levels maintain the fluid balance in the brain.