Endangered species are a concern to conservationists because there’s a risk that the animals won’t be able to adapt to their environment. one main cause of the inability to adapt is a)low genetic diversity b)a high rate of genetic mutation c)reproduction with an unrelated mate. both natural forces and human activities cause the endangerment of species. one situation that can be caused by both nature and humans is a)forest fires b)the burning of fossil fuels c)the removal of trees for lumber .

In which of the following ways is the function of the surface of a microsphere similar to the function of an actual cell membrane? a. both make it possible for the conditions in the interior to be different from the conditions outside. b. both provide a barrier that keeps water from flowing across it so the interior remains dry. c. both separate the rna that forms in the interior from any rna that might form in the environment. d. both can actively move molecules into the interior or out into the surrounding environment.

Based on the law of dominance, we would expect percent of the offspring from this cross to have large teeth.

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.