What is one of the ways in which sterility is ensured in single-dose vials? a. any leftover medication in a vial must be discarded, not saved for later use. b. the contents of a vial should be drawn out and administered using a syringe only. c. all vials must be sterilized immediately after use to prevent any adherence of impurities. d. vials are generally coated with an antibacterial film.

Which of the following viruses would most likely have reverse transcriptase? a) an rna-based lytic virusb) an rna-based lysogenic virusc) a dna-based lytic virusd) a dna-based lysogenic virus

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.

Which action occurs in the third stage of cell division a. the nuclear material of a cell is copied exactly b. the nuclear membrane disappears c. the cell forms two nuclei or d. the nuclear material separates, with half moving to wither side of the cell