need answer asap. as children grow older, their bones grow too. the growth of the long bones happens in a plate near the end of each bone. what happens to the cells of cartilage in a growth plate? a. cartilage cells are replaced by bone cells. b. cartilage cells lengthen to stretch out the bone. c. cartilage cells expand and become spongy bone cells. d. cartilage cells move into spongy bone as bone marrow.