Answer:
The answer is they are the source of new genetic variation.
Step-by-step explanation:
According to the U.S. National Library of Medicine, genetic variations can arise from gene mutations or from genetic recombination. It is also mentioned that these variations can alter gene activity or protein function, introducing this way different traits in an organism. So, if this trait has good results, it most likely will be shown in the next generation. This process is known as natural selection.