Why did robert e. lee turn down the offer to become a top commander in the union army?

a. he was a fierce supporter of the continuation of slavery in the south.
b. he had a long-lasting feud with jefferson davis.
c. he questioned the legitimacy of president lincoln's election.
d. virginia, his home state, had joined the confederacy.

its d

The constant presence of diseases or infectious agents within a given geographic area or population group. it may also refer to the usual prevalence of a given disease with such area or group. it includes holoendemic and hyperendemic diseases. a holoendemic disease is one for which a high prevalent level of infection begins early in life and affects most of the child population, leading to a state of equilibrium such that the adult population shows evidence of the disease much less commonly than do children (malaria in many communities is a holoendemic disease). a hyperendemic disease is one that is constantly present at a high incidence and/or prevalence rate and affects all groups equally. so probably family history.