The variety in a species comes through _______________ in DNA. When a new and helpful mutation arises, it will help individuals in the species to better ________________. Over the following generations, the new trait will become more prominent in a population (or even essential) since it increases the chances of ________________. (For example, the first bats to fly would have had an advantage over other bats who did not have the new genes necessary. The flight gene likely _____________ quickly during the following generations since it is so useful for survival.)
