The correct answer is that Americans had the God-given right to settle the entire North American continent.
In the 19th century, Americans believed that the expansión of the U.S. territory was inevitable, and the government decided to displace native Americans tribes. The manifest destiny justifies the expansion because Americans had the God-given right to settle the entire North American continent.
White people wanted more farmland. In 1830, there was less farmland in the East of the country. That is why they wanted to expand to the West. One of the leaders that supported the manifest destiny was President James K. Polk. In 1844. during his campaign, he made the commitment to acquire new territory.