In addition to military takeovers, some west african nations have suffered from
a. industrial pollution
b. war between groups
c. foreign invasion
d. natural disasters

Which example is a indication of stress a. becoming more alert b. narrowing air passages c. slowing down if the heartbeat d. decreasing blood sugar with adrenaline

Why would one lymph node in the neck be swollen and not the other? what causes them to swell?

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.