How do arteries differ in structure from capillaries and veins?
a)arteries have more elastin in tissue than veins and capillaries.
b) arteries appear flatter in a cross section than veins and capillaries.
c) arteries have valves which are absent in veins and capillaries.
d) arteries have walls that are thinner than veins and capillaries.

Why does meiosis produce cells with half the chromosomes? o a. most of the chromosomes are not necessary to keep an organism alive. b. a gamete needs only half the number of chromosomes because two gametes join together. o c. it makes the gametes easier to move around in the organism. o d. it is faster to produce gametes with fewer chromosomes.

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?

Wich level of organization includes all the other levels or organizations