Question

alpha particles cannot penetrate the skin. in which of the following circumstances could they still threaten human health?

a. if they enter into the human ear.

b. if they are touched.

c. if they are inhaled or swallowed.

d. if they travel into the human eye.

Explanation:

Alpha particles can't penetrate the skin, but if they are inhaled or swallowed, they can enter the body's internal tissues (like lungs or digestive system). Once inside, their ionizing radiation can damage cells and DNA, posing a health threat. Touching them (B) or entering ear/eye (A, D) without internal entry won't let them reach vulnerable internal tissues as effectively as inhalation/swallowing.

Answer:

C. If they are inhaled or swallowed.