Which statement is true of cancer? A) cancer results when cells stop dividing. B) mutations in certain genes caue tumors. C) tumor cells lack growth factors and DNA. D) DNA mutations are unrelated to cancer.

B) Mutations in certain genes cause tumors.

The development of cancer is often the result of mutations in genes that regulate cell growth and division. These genes can be broadly classified into two main groups:

1. Oncogenes: These are mutated forms of genes that when activated can promote cell growth and division in an uncontrolled manner.

2. Tumor suppressor genes: These are genes that normally help prevent uncontrolled cell growth. Mutations that deactivate tumor suppressor genes can lead to cancer because they remove restraints on cell division.

These genetic mutations can be inherited or acquired during a person's lifetime due to factors such as exposure to carcinogens (cancer-causing substances), radiation, smoking, viruses, and random errors during cell division. When these mutations accumulate, they can lead to the formation of a tumor, which is a mass of cancerous cells.