Read the following passage from the biology department at university of california, berkeley. northern elephant seals have reduced genetic variation because hunting by humans reduced their population size to as few as 20 individuals at the end of the 19th century. their population has since rebounded to over 30,000, but their genes still carry the marks of this near extinction: they have much less genetic variation than a population of southern elephant seals that was not hunted as intensely. which of the following best describes how the population has evolved? a. the population has not evolved because there was no change in allele frequencies. b. the population has not evolved because it has grown. c. the population has evolved because it has grown. d. the population has evolved because there was a change in allele frequencies.

The population has evolved because there was a change in allele frequencies.

Explanation:

The evolution may be defined as the process of the change of the species characteristics with the passage of the time. The natural selection, mutation and the genetic drift might cause the evolution.

The population might have evolved as the allele frequencies has changed from the generation to the generation. Although the variation among the population is quite less but the variation is still enough for the evolution of the elephant seals.

Thus, the correct answer is option (D).

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.