In ming china, why did european traders pay for chinese silks and porcelains in gold or silver instead of exchanging trade goods?

Well, they prefered gold and silver because the Chinese did not want inferior european trade goods, so European traders had nothing else to offer.

They can ask questions and they deserve a answer and they can make stories about whatever is going on in the white house

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.