What is the “Big Mac Index"? A. an analysis of purchasing power using the price of Big Macs in different countries
B. a way for new employees at a McDonald's to be sure their Big Macs are made correctly
C. a method for customers to suggest improvements to the food at McDonald's
D. an international measurement for how large Big Macs are

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.

Race, for example, the chinese exclusion act