7. Challenge yourself: You have already learned that mutation is one source of variation in a population. Based on what you have just seen, what is a second
source of variation?
(I just need more information or explanation) please

Natural selection would be the other source because organisms that have a beneficial trait will live, but organisms that do not have a beneficial trait might die. So the organsims that do survive will reproduce and pass on those traits to their offspring. Eventually all the organisms that do not have a beneficial trait will die out, leaving most of the population having that beneficial trait.