Which pushed the united states to go to war against mexico in 1846?
a. manifest destiny and a desire to extend slavery into mexican territory
b. an invasion by the mexican army into the southwestern united states
c. years of failed negotiations over the disputed oregon border
d. arguments in favor of war from abraham lincoln and others in congress

I think the answer is B)an invasion by the Mexican army into the southwestern United States

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.