Which of the following is a characteristic of external exposure to radiation?

External exposure to radiation includes any exposure to radiation from sources outside the body, and one of its defining characteristics is that it can indeed originate from both natural and artificial sources. Natural sources include cosmic rays, radon gas, and terrestrial radiation, while artificial sources can encompass medical imaging, radiation therapy, and nuclear power generation.

This characteristic highlights the diversity of radiation exposure pathways. For example, individuals may encounter natural radiation simply from their environment, while artificial sources can contribute significantly in specific contexts, such as healthcare settings. Understanding that both types exist is crucial for evaluating radiation safety and exposure risks in various environments.

The other options don't accurately reflect the nature of external radiation exposure. It does not exclusively happen during medical procedures, it can increase cancer risk depending on the dose and duration of exposure, and detection may vary but is typically not inherently easier than detecting internal exposure, as both require specific measurement techniques and considerations. Thus, identifying that external radiation exposure can come from both natural and artificial sources provides a more comprehensive understanding of radiation risks and safety measures.