As the Spanish flu progressed across the United States, a unique characteristic that emerged was that the disease...
a) seemed to be without symptoms at the end
b) killed mostly young, healthy adults
c)struck a disproportionate number of people in new england
d) killed a disproportionate number of women

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.