Explain why the major causes of death are different for adults and teens.

David, an aspiring baseball player, was struck on the left side of his face with a fastball pitch. he was not wearing a safety helmet. his zygomatic arch was crushed, as well as parts of the temporal bone. following the accident and reconstructive surgery, he noted that his left lower eyelid was still drooping and the corner of his mouth sagged. what nerve damage did he sustain?

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.

Why do rna viruses appear to have higher rates of mutation? a) rna nucleotides are more unstable than dna nucleotides. b) replication of their genomes does not involve proofreading. c) rna viruses can incorporate a variety of nonstandard bases. d) rna viruses are more sensitive to mutagens.