Which factor most contributed to the huge casualties suffered by the combatants in World War 1 A. the development of development of devastating new weapons Technologies B. the refusal of crom Manders to attacked and no-man's land C. the targeting of civilians by US military forces D. the collapse of Russian Omen and Austro-Hungarian Empires​

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.