Question

which statement best defines the term cancer?
a. cancers occur when normal cells grow rapidly.
b. cancers are normal growths that occur in all tissues.
c. cancers are tissues that grow in abnormal places.
d. cancers occur when abnormal cells grow uncontrollably.

Explanation:

• Option A: Normal cells growing rapidly is not the definition of cancer. Normal cells can grow rapidly in some normal processes (e.g., during wound healing).
• Option B: Cancers are not normal growths. Normal growths are regulated, while cancers are unregulated.
• Option C: Growth in abnormal places is not the key definition. Metastasis (spread to abnormal places) is a later stage, but the core is uncontrolled growth.
• Option D: Cancer is characterized by abnormal cells (due to genetic mutations etc.) that grow in an uncontrolled manner.

Answer:

D. Cancers occur when abnormal cells grow uncontrollably.