Which of the following is NOT a way radioactive material can enter the body?

Radioactive materials can enter the body through various pathways, and understanding these routes is crucial for assessing exposure risks. Inhalation refers to the process where radioactive particles are breathed in and enter the lungs, which can lead to internal contamination. Absorption occurs when radioactive substances penetrate the skin or mucous membranes, allowing entry into the bloodstream. Ingestion involves consuming food, water, or substances that contain radioactive materials, leading to contamination within the digestive tract.

Injection, while a common method for various substances, is not typically a recognized pathway for radioactive material to enter the body in the context of environmental exposure. It is more applicable to medical contexts where radioactive isotopes might be purposely injected for diagnostic or therapeutic purposes. Thus, injection does not represent a natural or environmental route, which is why it is seen as not being a standard method for radioactive material entry into the body.