Imagine an active, employed sixty-year-old who does not have dementia. Which of the following statements offers an explanation why he might not be as good at forming memories as he was when younger? A. He has lost too many synapses through underuse.

B. He is not as emotional as he once was.

C. His brain is no longer making new neurons.

D. He has too many neurofibrillary tangles.

Which are fat-soluble vitamins? a. abcd b. abek c. abdk d. acdk e. adek

What is a good description of wellness

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.