Which of the following is one reason that nationalism grew so widely in europe in the first part of the twentieth century?
a. more countries came into existence
b. more people could vote
c. kings and queens promoted it
d. communism was popular

I would say because more countries came into existence, because people were trying to cling to their culture and their country as other countries rose up around them.

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.