In animals, enzymes and hormones are similar in that both substances:
A. must be ingested.
B. function only within cells.
C. are products of cell synthesis.
D. do not contain the element nitrogen.
Enzymes and hormones must be made within cells, or synthesized (not ingested). They are large proteins so they, in fact, do contain nitrogen. They are secreted outside of the cells and are used in digestive organs (enzymes) or travel through the blood to affect other body parts (hormones).