What is the reason why children generally would be more sensitive to the effects of radiation?

• A. Their bodies are smaller
• B. Their body parts are thinner
• C. Their mitotic activity is higher
• D. They are not as capable of cooperation

Answer: (C)

Rapid cellular proliferation drives radiosensitivity. In children, growth and development involve many cells that are actively dividing, especially in bone marrow, the lining of the gut, and developing organs. When ionizing radiation damages DNA, cells in mitosis have less opportunity to repair before division, so damage more readily leads to cell death or mutations. A larger fraction of a child’s cells are in these sensitive, dividing stages, making tissues more susceptible to radiation and raising the risk of both immediate and long-term effects.

The other factors—smaller body size or thinner tissues—don’t inherently increase the biological sensitivity of cells to radiation, and a patient’s ability to cooperate doesn’t influence how radiation affects cellular biology.