Answer:
They decrease Native American population
Explanation:
The Christian missionaries at the time carried a lot of disease that never been encountered by the Native American (such as Measles and chicken pox). Since the Native American population did not have immunity to these diseases, the infection rate was very high.
This resulted in a lot of deaths among the Native American people since they did not have the medical knowledge to cure it. Years after the initial infection, the native American population in oregon country was massively decreased.
