Trisomy 21 can be caused by nondisjunction of chromosome 21, or by inheriting a Robertsonian fusion of chromosome 21 attached to chromosome 14. Suppose an individual is a carrier for this Robertsonian fusion, as seen below. How many different gametes can this individual produce?

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.

Select all that apply. why are common names not a good reference to a species? common names can be in different languages common names vary with location common names vary with culture common names vary with species color

He did not infringe upon the policy making powers that he felt the constitution gave congress. but the determination of foreign policy became preponderantly a presidential concern. when the french revolution led to a major war between france and england, washington refused to accept entirely the recommendations of either his secretary of state thomas jefferson, who was pro-french, or his secretary of the treasury alexander hamilton, who was pro-british. rather, he insisted upon a neutral course until the united states could grow stronger. which provides the best objective summary of this excerpt? president washington made a good choice when he decided not to accept the recommendations of his advisors and instead insisted that the united states stay neutral during the war between france and england as president, washington believed that the united states should remain neutral in foreign policy even though he had advisors who recommended that he take sides during the war between france and england. washington did not make policy decisions during his presidency because he did not want to interfere with the policy-making powers that the constitution gave congress. washington refused to accept entirely the recommendations of either his secretary of state thomas jefferson, who was pro-french, or his secretary of the treasury alexander hamilton, who was pro-britis