What is a mutagen?

A mutagen is specifically defined as a substance that causes genetic changes, which can lead to mutations in the DNA of organisms. These changes can occur in various forms, including alterations to the DNA sequence, which may affect how genes function or are expressed. This definition encompasses a wide range of agents, from chemicals and radiation to certain biological factors, all of which have the potential to induce genetic modifications that could result in harmful effects on organisms, including humans.

Understanding the role of mutagens is crucial, especially in fields such as genetics, microbiology, and environmental science, where the implications of genetic changes can have significant health, ecological, and evolutionary consequences. The other options describe different categories of substances that do not directly relate to the concept of mutagens. For example, agents that enhance growth and those that control pests pertain more to agricultural practices, while chemicals that promote decay are associated with decomposition processes. Recognizing the distinct definition of a mutagen helps clarify its role in both environmental and health contexts.