Apopulation that is becoming less diverse because of its individuals tending to be larger is most likely experiencing
selection.

A population that is becoming less diverse because of its individuals tending to be larger is most likely experiencing directional selection.

Further Explanation:

Natural selection is the phenomenon by which organisms adapt to the changing environmental conditions to increase their fitness in that environment. These traits are even passed on to the next generation. The mate selection tendency does not depend upon natural selection.The three different types of natural selection are:

• Disruptive selection

• Directional selection

• Stabilizing selection

The directional selection allows the extremes, and thus, due to the elimination of intermediary phenotypes, both the variation and average phenotype change. The allele frequency, which is fit for survival, is favored, and the whole population shift for that allele frequency and result in less diversity. A particular trait is favored in one direction because of natural selection. In this selection, there is no connection between fitness and allelic frequency. The differences in the different color types are not affected by the frequency.  

Learn more:

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3. Learn more about phospholipids

Answer Details:

Grade: High School

Subject: Biology

Chapter: Evolution

Keywords:

Directional, selection, stabilizing, disruptive, whole, natural selection, allele frequency, color, organism, adapt, tendency, mate selection.

the answer for this question would be d. glaciers