Hormones that consist of three or more amino acids are

a. steroids.
b. amines.
c. peptides.
d. prostaglandins.

Agroup of 50 adult male humans were in a clinical study to determine how much niacin is toxic. during the first two weeks of the study, members of the group consumed only a formula diet that was nutritionally complete, except it contained 24 mg niacin, which is 1.5 times the rda for niacin (males). at that point in the study, all members reported feeling fine. during the next week, they were given a formula that contained 48 mg niacin. within a few days of consuming this formula, 90% of the participants reported feeling ill, and they complained of having upset stomachs and reddened facial skin. at that point, researchers gave the subjects a formula that contain 16 mg niacin. after a week of consuming the new formula, all participants reported feeling well again. based on this information, the researchers concluded that the amdr for niacin is between 16 and 24 mg/day. ul for niacin was between 24 and 48 mg/day. human requirement for niacin is 16 mg/day. eer for niacin was 16 mg/day.

Viruses use the host's machinery to make copies of themselves. however, some human viruses require a type of replication that humans do not normally have. for example, humans normally do not have the ability to convert rna into dna. how can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires? a) the virus causes mutations in the human cells, resulting in the formation of new enzymes that are capable of performing these roles.b) the viral genome codes for specialized enzymes not in the host.c) the virus infects only those cells and species that can perform all the replication roles necessary.d) viruses can stay in a quiescent state until the host cell evolves this ability.

Explain different ways infections from different organisms can be treated.