Scientists use squid nerve cells in research because the nerve cells of a squid are 1,000 times fatter than those of a human. how is the outcome of nerve cell research most likely to be affected if scientists were to study human nerve cells directly?
the outcome would be different because humans and squids are very different.
the outcome would be different because the nerve cells in squids are much larger than those of humans.
the outcome would be the same because in both cases a nerve cell is being researched.
the outcome would be the same because genes in squids and humans are 85 percent identical.

In the family tree below, people with the recessive trait of attached earlobes are shaded gray.

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.

Explain why biological control methods are generally environmentally superior to chemical pest control methods.