HELP PLZ Why are unrepaired gene mutations bad?
They make proteins with normal functions.
Their changes can be easily undone by DNA.
They affect the structure of proteins.
The affected chromosomes recoup and repair.

They affect the structure of proteins.

Explanation:

A mutation is any change that occurs to the nucleotide sequence of a gene. A Gene is a segment of the genetic material (DNA) that encodes the protein needed for the growth and development of an organism. Hence, a change in the nucleotide sequence of a gene (mutation) will alter the structure of that protein that the gene encodes.

A protein function is attributed to its structure, hence, once the structure is altered because of unrepaired gene mutations bad, the protein loses functionality. This is why unrepaired gene mutations are bad.