1 . What happens in the population if the mutation phenotype is helpful 2. Why does that happen for that population that has a helpful phenotype?

3. How does this mutation continue to exist in a population?

correct answer is a. and d.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.