Answer:
Cancer develops when the body's normal control mechanism stops working. Old cells do not die and instead grow out of control, forming new, abnormal cells. These extra cells may form a mass of tissue, called a tumor. Some cancers, such as leukemia, do not form tumors.
Explanation:
B. nucleus which is the brain of a cell
Answer: a
Explanation: cel walls have thick and rigid structure with a fixed shape while cell membranes have a thin and delicate structure