Which of the following are two mechanisms for water pollution?
a.
high and low
b.
direct and indirect
c.
lethal and nonlethal
d.
harmful and innocuous

If a person has a bad pain in their back, specifically lower back a bit above the hip, what should they do besides going to the doctor? what remedies could they use?

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.

The only infectious disease that was a top-ten killer of americans in 1900 that is still a top-ten killer in 1990 is hiv/aids select one: true false