What is the general term for a substance that is harmful to life and may cause death?
a. benign
b. hypoallergenic
c. innocuous
d. toxic

James is sitting at his desk on the ground floor of an office building when the entire room starts shaking. which action is most appropriate in this situation? a. standing near a window b. running out of the building c. holding up a bookshelf d. preparing for aftershocks

Which describes the effect of prolonged stress on blood pressure? it causes blood pressure to decrease. it has little or no effect on blood pressure. it causes the heart to pump with more force. it causes blood pressure to increase.

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.