What was a major factor that helped Washington’s population to increase after 1883?

The population of Idaho, Oregon, and Washington in 1880 amounted to more after the arrival of transcontinental lines during the 1880s, the substantial increase resulted in large part from the arrival of railroads, railroads helped to disseminate the modernizing ways of the late 19th century.

Explanation:

u.s.a

china

india

and

japan

c-three

explanation:

legislative, executive and judicial