Answer:
somatic mutations
Explanation:
"Not all mutations are evolutionarily important. Somatic mutations occur in body cells and cannot be passed down from parent to offspring. Cancer, for example, is a mutation of body cells which causes unrestrained growth. Although cancer can be deadly for an individual organism, it is not passed from one generation to another. Only mutations in reproductive cells, like eggs and sperm, matter in evolution because they can be inherited by offspring."
