The double walled membranous sac that encloses the heart is the

Humans are believed to have evolved in coastal regions in east africa. the region had an abundant supply of fish for early humanoids to eat. when scientists analyze the fads gene they see an interesting pattern. people whose families have lived in this area of east africa for generation show a high level of diversity in alleles for the fads gene. conversely, people whose families had migrated inland a moderate distance from sources of fish showed a much lower diversity for fads gene alleles. additionally, the fads alleles found in people whose family has lived inland for generation are almost all gene alleles which produce fads proteins with a high level of function and activity. how do anthropologists explain this?

Body temperature is tightly regulated in mammals for example when external temperatures drop too much the body of a mammal response by in order to it's core temperature.

The diagram shows the results when two parents are crossed. the letters represent alleles for a trait that is controlled by three different genes. which best describes this inheritance pattern? multiple allele because a trait is controlled by three different genes polygenic because the offspring have alleles from both parents multiple allele because the offspring have alleles from both parents polygenic because a trait is controlled by three different genes