Answer:
Southern slaveowners or those who aspired to own slaves were vocal proponents of westward expansion. These Southerners wanted to move west to settle the west's fertile soil and grow cotton. In the west, there was a chance for Southerners to get a larger plantation than in the east. There was less competition.
Explanation:
The climate east of the Cascades is markedly different, a continental climate of cold, snowy winters and warm, dry summers. ... Climate also affects growing seasons in the Columbia River Basin. At higher elevations, the season can last as few as 30 days.
