27.Answer the following with respect to …

a. Cancer cells differ from normal cells in many ways that allow them to grow out of control and become invasive. One important difference is that cancer cells are less specialized than normal cells. That is, whereas normal cells mature into very distinct cell types with specific functions, cancer cells do not.

b. When the cells in the tumor are normal, it is benign. Something just went wrong, and they overgrew and produced a lump. When the cells are abnormal and can grow uncontrollably, they are cancerous cells, and the tumor is malignant. A malignant tumor has the ability to spread to other tissues and to initiate tumors at secondary sites, whereas a benign tumor does not spread.

c. The exact cause of a benign tumor is often unknown. It develops when cells in the body divide and grow at an excessive rate. Typically, the body is able to balance cell growth and division.