Which best describes genetic mutations?

A mutation is any change in the number or structure of a chromosome. The image you see here shows damaged DNA. There are several possible causes of mutations, such as radiation damage or chemical exposure. Sometimes, segments or entire chromosomes are deleted and not passed on to the new cell. Other times, the patterns are mixed up or made backwards. All of these mutations cause changes in normal patterns and result in new chromosome formations.

I’d say a : water molecules