In the post-reconstruction era most african-americans in the south had little opportunity for economic advancement, and worked mainly as

In the post-Reconstruction era and worked mainly as SHARE CROPPERS.
Share cropping system arise in the South during the post construction era as a result of the economic difficulty that was brought about by the  civil war and the abolition of slavery. Share cropping refers to the type of farming in which a family rent a plot of land from a landlord in return for a specified portion of the harvest which will be given to the landlord during the harvesting period. This type of farming was majorly practiced by former slaves who have no land of their own.

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.