Answer:
The correct answer is:
a) alpha.
Explanation:
Alpha radiation consists of alpha particles, which are positively charged particles consisting of two protons and two neutrons (essentially a helium nucleus). Alpha radiation is generally not considered a significant external hazard because it has low penetration power and can be stopped by a piece of paper or human skin.
However, alpha radiation can be hazardous if the source of alpha particles is inhaled or ingested. Once inside the body, alpha particles can damage tissue and organs, potentially leading to adverse health effects such as cancer. Therefore, alpha-emitting materials pose a significant hazard if they are inhaled or ingested.
