During the 1840s, supporters of manifest destiny favored

 Westward expansion.

Explanation:  Both government and individual felt nothing should stop the all-powerful drive to expand the size of the country.

from the conditions of the working class in england by friedrich engels,the main idea is :

interdependence is when all participating groups and individuals depend on each other. if you depend on one anothers goods, you end up trading in order to get the items you're looking for. (for ex: if i have food and you have water, we trade in order to depend on each other to live)