Which statement is TRUE about the heart valves and blood flow through the heart? A. Oxygenated blood enters the left atrium and is pushed through the bicuspid valve to the left ventricle.
B. Deoxygenated blood enters the right atrium and is pushed through the semilunar valve to the right ventricle.
C. Deoxygenated blood enters the left atrium and is pushed through the tricuspid valve to the left ventricle.
D. Oxygenated blood enters the right atrium and is pushed through the bicuspid valve to the right ventricle.

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.