Which person would be the least effective host for a pathogen? •an older person
•a young athlete
•a smoker
•a sick person

A72-year-old woman fell in her bathtub and fractured her hip. in viewing the fracture, x-ray revealed osteoporotic changes in her bone as well. after reduction of the fracture, and immobilizing the bones with internal pins, what type of exercise would the doctor have advised her to do as soon as she was able in addition to prescribing calcium supplements to improve her bone mass?

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.

What is a possible consequence of abusing intravenous drug such as heroin? a-hiv transmission b-alcohol poisoning c-improving appetite d-lung cancer