Final answer:
Cancer is defined as a series of diseases where abnormal cells grow uncontrollably, potentially spreading to other body parts and forming tumors. It occurs due to a breakdown in the regulation of the cell cycle typically because of DNA damage.
Step-by-step explanation:
Definition of Cancer
The term cancer defines a group of diseases characterized by the uncontrollable growth of abnormal cells. These cells have the potential to invade or spread to other parts of the body, forming a mass known as a tumor. Cancers result from DNA damage that leads to the loss of normal cell cycle regulation, possibly due to various risk factors, including exposure to carcinogens such as radiation or chemicals. The progression of cancer involves the aggressive multiplication of these abnormal cells, disrupting normal bodily functions and potentially leading to death if not treated.
Best Definition
The best definition of cancer among the choices provided would be: D. Cancers occur when abnormal cells grow uncontrollably. This statement captures the essence of cancer, emphasizing the abnormal and unrestrained nature of the cell growth that characterizes the disease.