What are the tiny particles that make up matter called?

The correct choice refers to atoms, which are the fundamental building blocks of matter. Atoms are the smallest units of an element that retain the chemical properties of that element. Each atom consists of a nucleus, which contains protons and neutrons, and is surrounded by a cloud of electrons.

Understanding atoms is crucial in fields like radiation safety and protection because radioactive materials consist of unstable atoms that can emit particles or radiation during decay. This knowledge is essential when considering the interactions of radiation with matter and the potential health effects of exposure.

In contrast, electrons and protons are subatomic particles found within atoms, and while molecules consist of two or more atoms bonded together, they do not constitute the smallest units of matter alone. Therefore, atoms serve as the foundational units from which all matter is constructed, emphasizing their importance in the study of radiation and safety practices.