Answer:
American Americans were allowed to join armed forces
Ummm...I think that's the oath that states the obligations and proper conduct of doctors, formerly taken by those beginning medical practice. Parts of the oath are still used in most medical schools.
I believe it’s improved transportation
Answer:
Throughout the mid-1880s, the Northern Pacific pushed to reach Puget Sound directly, rather than by means of a roundabout route that followed the Columbia River. Surveys of the Cascade Mountains, carried out intermittently since the 1870s, began anew.