GED Science Practice 2026 - Free GED Science Practice Questions and Study Guide

Radioactivity involves the spontaneous emission of particles or electromagnetic rays resulting from the decay of unstable atomic nuclei. This process occurs as certain isotopes seek to attain a more stable configuration. During this decay, energy is released in the form of radiation, which can include alpha particles, beta particles, and gamma rays. This characteristic is essential in understanding nuclear reactions, the behavior of radioactive substances, and their applications in fields such as medicine, energy, and research.

The other options relate to different concepts. Some involve reuse or recycling processes, while others pertain to thermal energy transfer or general forms of radiation that do not specifically address the unique characteristics of nuclear decay associated with radioactivity. Thus, the most accurate representation of what radioactivity entails is the spontaneous emission resulting from nuclear decay.