Which of the following is caused by radiation exposure to the human body?

• A. radioactivity
• B. protein synthesis
• C. ionization
• D. infection

Answer: (C)

Ionization is the primary effect of radiation exposure on the body. When ionizing radiation interacts with atoms in tissues, it has enough energy to remove electrons, creating charged particles (ions). This direct interaction can damage cellular components, including DNA, and produce free radicals from water in the cells, leading to chemical changes and potential biological harm.

Radioactivity would mean the body is emitting radiation due to internal radioactive material, not merely being exposed; protein synthesis is a normal cellular process that can be disrupted by radiation but is not the immediate cause of exposure; infection is caused by pathogens, not radiation. Ionization directly results from the radiation interacting with matter in the body.