Which of these was a challenge formany people who traveled to the West? Select one:
. a. Great Plains
b. Missouri River
c. Pacific Ocean
d. Rocky Mountains

D. Rocky Mountains

Explanation:

After entering the mountains, the trail became much more difficult, with steep ascents and descents over rocky terrain. The pioneers risked injury from overturned and runaway wagons.

answer: ensure protection from communism

explanation:

the north atlantic treaty was largely dormant until the korean war initiated the establishment of nato to implement it, by means of an integrated military structure: this included the formation of supreme headquarters allied powers europe in 1951, which adopted the western union's military structures and plans.