Natural selection explains the differential reproduction of individuals within a population due to variation in relevant phenotypic traits. When these traits contribute to a higher rate of reproductive success, then they are described as:-

Microevolution

Explanation:

Microevolution is caused when fit or adaptive allele (phenotypic  traits) is passed from one generation to another  through reproductive success over time. Natural selection (fitness) which is mostly dependent on how successful and organism reproduces and survive influence an organism's phenotype.  These phenotypic traits is large a product of alleles, or genes an organism possesses

FITTEST;with dominant trait

Explanation:

Fitness is used to describe the   reproductive  success  of an organisms compare to  others in the same population.These fitted organisms are able to resist the environmental pressures, and are naturally  selected  due certain hereditary traits which contributes to their fitness called adaptation.

Therefore when these traits contributed to  higher rate of reproductive success, then they are describe to be the fittest, well adapted and therefore naturally selected in the population.

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.

not only is it colder, it also becomes darker, less salty, and more dense.