Cellular respiration occurs in animals and plants
We know that height in humans is a polygenic trait because it has a lot of variation. The height gene is controlled by at minimum three genes with six different alleles. If all of these alleles are dominant for the tall gene you will be tall if you are dominant for the short gene you will be short if there is no clear dominance between the two genes you will fall somewhere in the middle.
The skin is cooled through evaporation.
Answer: Directional selection occurs when individuals with traits on one side of the mean in their population survive better or reproduce more than those on the other. ... Directional selection does the “heavy lifting” of evolution by tending to move the trait mean toward the optimum for the environment.