Once Europeans arrived, what killed a large number of Native Americans, impacting Native American populations for decades after?

smallpox

Explanation:

the europeans arrived to america with a disease called smallpox and since the indigenous people had never experienced it before, it wiped out 90% of the population

Diseases. The immunity of the Native Americans had not been exposed to the diseases brought by the Europeans. Therefor, their bodies lacked the ability to fight the diseases causing many to die and the diseases spread rapidly. Examples of these diseases were: small pox, influenza, measles, and chicken pox.

Explanation:

no options provided, here,but the answer to this question is often: a historian cites a japanese newspaper article published a year after the end of world war ii in order to draw conclusions about the effect of the war on the japanese economy.

clearly from the answer, the historian alludes to historical sources,and records to aid in analyzing and drawing conclusion on the effect of the war on the economy of japan.