The correct answer is A) building shelters.
The pioneers’ first priority was building shelters.
Life was difficult for pioneers who decided to leave their former lands and travel to the west in the time if US history called "the westward expansion." The Oregon Trail was also a difficult road to cross. Many people could complete it. Hunger was a major issue.
Pioneers had to build their shelters to endure climate conditions, clear the land for farming. However, the opportunity to have their own portion of land motivated many farjmers, former slaves, and immigrants.
We should know about this because American Citizens need to know how we won the war.
A and B, they pillaged and traded with other countries throughout the course of history, and in order to do this they needed to travel by water given that trees were readily available to make boats. This helped them survive throughout history.
1945-1952 is the time period.
