What is a mutation?

A mutation refers to a genetic alteration in the DNA sequence. This can occur in various forms, such as point mutations, insertions, or deletions, and it can affect a single nucleotide or larger segments of DNA. These alterations can lead to changes in the proteins produced by the genes, which may impact the organism's traits, functionalities, and overall biological processes.

Understanding mutations is crucial, as they are a key factor in evolution, genetic diversity, and the emergence of certain diseases. While the other options mention important biological concepts, they do not precisely define what a mutation is. For instance, a change in protein structure is a potential consequence of a mutation but not a definition. Likewise, environmental influences can affect gene expression but are not mutations in themselves, and the process of cell division, though it can involve mutations, is a separate mechanism from the definition of a mutation.