Q: Fact 1: Cancer is a disease in which cells divide out of control. Fact 2: Cancer is a disease of aging. Given the two facts above, what causes cells to divide?

Choose your answer from:
(1). fever;
(2). glucose;
(3). Smoking;
(4). aging;
(5). alleles;
(6). fungi;
(7). Light;
(8). heat;
The answer is:
(4).