why were the lewis and clark journals and notes from the lewis and clark expedition important to westward expansion

Lewis and Clark's team mapped uncharted land, rivers, and mountains. They brought back journals filled with details about Native American tribes and scientific notes about plants and animals they'd never seen before. ... Many Americans did more than dream. The great westward expansion was about to begin.

d is the best answer for this question.

i believe the correct answer is option b. most eastern european nations joined nato.

though i could be wrong, option d. the eastern european nations were granted complete independence, would be another choice.

hope this ! : )