Which of the following is not a source of generic variation ?

a. mutations
b. lateral gone transfer
c. asexual reproduction
d. sexual reproduction

Asexual reproduction is not a source of genetic variation.

hope this helps ( :

the answer would be d : p

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.