Mr. Smith has found a lump under his arm. He goes to his doctor, and the doctor confirms that the lump is cancer. How are cancerous cells different from normal cells?
A.
the growth-regulating genes of cancer cells have mutated
B.
cancer cells occur in adults but not in children
C.
cancer cells are found in the lymph; normal cells are not
D.
carcinogens change cancer cells to normal cells