Answer:
C. Characters with little genetic variation will constrain the rate of natural selection
Explanation:
Natural selection can have an effect only as long as there are variations on characters on which it can select upon. Genetic variation is independent of the environment or the needs that a species may have to become better adapted to its changing environment. In other words, genetic mutations are the raw material on which natural selection can work. If there is a low rate for mutations to occur, then natural selection will proceed at a slow pace. The opposite is also true. Since mutation rate may be more frequent at some locations in a gene than at others, it can be predicted that the characters coded in that gene location will be more likely to be affected by natural selection and therefore what phenotype may be molded by natural selection.
Statement D. Is not true.
Allopatric speciation, also referred to as geographic speciation, is a method of the formation of new species due to isolation of the species from one another through geographic means.
The first step in this process is geographic isolation, which means that the original population is divided into two groups due to geographical reasons such as movement of continents or formation of water bodies.
Next, the species are subjected to different selection pressures due to their different environments. Eventually, the gene pool becomes very different for the two species due to the different selection pressures and because they are not allowed to mix.
Finally, after enough time passes, speciation occurs, which means that the two populations cannot breed to form fertile offspring.