What is a mutation?

A mutation is defined as a heritable change in genetic material. This means that the alteration can be passed down from one generation to the next through reproduction. When a mutation occurs in the DNA sequence, it can affect the way genes are expressed or how proteins are produced, which can lead to changes in an organism's traits or characteristics.

The key aspect of mutations is their heritability, implying that they can be transmitted to offspring and contribute to evolutionary changes over time. This process is vital in the context of natural selection and genetic diversity within populations.

Furthermore, mutations can occur in both somatic cells and germ cells, but only those in germ cells are passed to the next generation. The option that suggests mutations occur only in somatic cells misses this important distinction. Similarly, the choices that describe mutations as non-heritable or as processes that only impact proteins do not encapsulate the full definition and implications of what a mutation truly is. A mutation can have widespread consequences on genetic variation and evolutionary biology.