Which best describes cancer cells? cancer cells cannot enter the circulatory system. cancer cells grow controllably. cancer cells attach to organs. cancer cells lose nutrients to healthy cells.

Cancer cells are attached to organs. If not treated, the cancer cells can spread throughout the Circulatory system, causing mutations. So A is incorrect, including other options except C.

The correct option is this: CANCER CELLS  ATTACHED TO ORGANS.
Cancer cells are those cells that that have lost the ability to divide controably. Cancer cells undergo cell division without stopping thus leading to the development of cancerous tissues. These cells can form in any organ of the body. Many causes are responsible for the formation of cancer. Cancer cells has the ability to spread from one organ to another via the circulatory system. This property of cancer is called metastasis. 

Iguess i would say diagrams would be most difficult subject too correct