Explain how vaccines prevent infections

If babies are consistently placed on their backs without any restrictions, what will happen to their development? a. they suffer from weakness in certain muscle groups. b. their ability to roll over, crawl, and eventually walk is hindered. c. they suffer brain damage from the pressure on the back of the head. d. they learn to roll over, crawl, and eventually walk on their own.

Anne is 60 years old and rather frail. she fractured her forearm while playing with her grandson. that was two months ago, but her arm is still in a sling. which disease is she likely suffering from?

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.