Biochemistry - the study of the molecules that compose living organisms

Element - the simplest form of matter to have unique chemical properties

Trace Elements - An element indispensable for life but required in extremely minute amounts.

Radioisotopes - unstable isotopes

Radioactivity - the process of decay of Radioisotopes

Ionizing Radiation - Enough energy to dislodge electrons from atoms, forming ions; capable of causing cancer (gamma, X-rays, UV)

Physical Half-Life - the time required ...