TOEFL Listening: TPO-TOEFL阅读TPO - J9K_W9M93QYP6RIAN$

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. Geographic isolation is sometimes but not always the reason for the creation of reproductive barriers between a parent population and the populations descended from it B. Genetic changes in a geographical isolated population do not necessarily make the population look different enough from its parent population to be considered a new species C. Geographical isolation allows the separated populations to evolve independently of each other and so can lead to the formation of new species D. Geographic isolation can lead to new species only if the gene pool of the isolated population changes enough to prevent it from reproducing with the parent population