A) Genetic drift is the random increase or decrease of genes in a population. Natural selection is not random.
Genetic drift is the change in the frequencies of alleles in a population due to chance events (random survival). Genetic drift exhibits strong effects in small populations and plays a smaller role the larger the population gets. Natural selection is the non-random change in the frequency of alleles in a population over time, because the change in frequency of the alleles is dictated by the different relative fitnesses that different alleles confer.
Explanation: there not canyons so you can cross that off and its not the dunes nor the deltas so if you look at the picture you can tell it is the plateaus
Granules cross-link filaments of keratin making stratum granulosum a dense barrier. Since granules are insoluble and keratin structures are dense, the skin act as a impermeable layer.
