Cancer cells behave differently than normal body cells.For example, they ignore signals that tell them to stop dividing. Which of the following conditions will most likely cause a normal body cell to become a cancer cell? A The environment already contains cancer cells. B The environment has an abundance of nutrients. C The environment lacks signals that would otherwise tell the cell to stop dividing. C D The environment contains mutagens that induce mutations that affect cell-cycle regulator proteins.

## Step 1<br />The problem is asking us to identify the condition that is most likely to cause a normal body cell to become a cancer cell. <br /><br />## Step 2<br />We need to understand that cancer cells are abnormal cells that divide without control. They can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems.<br /><br />## Step 3<br />Looking at the options, we can see that option D states that the environment contains mutagens that induce mutations that affect cell-cycle regulator proteins. Mutagens are agents that cause genetic mutations. These mutations can lead to changes in the cell cycle, which can cause cells to divide uncontrollably, leading to cancer.<br /><br />## Step 4<br />Options A, B, and C do not directly cause a normal cell to become a cancer cell. The presence of cancer cells (option A), an abundance of nutrients (option B), or a lack of signals to stop dividing (option C) do not necessarily lead to the transformation of a normal cell into a cancer cell.