21. describe each of the four mechanisms that cause air to rise.(4 points)

1. Convective uplift. The hot air is less dense and it rises.
2. Orographic lifting. Air is forced to rise when it meets a mountain.
3. Convergence. Thunderstorms are caused by convergence.
4. Frontal wedging. When a cold air mass meets a warm air mass, the colder air wedges its way beneath the less dense warm air.
Mind marking this as Brainliest??

It is the doctrine that the us had the right and duty to expand throughout north america. it just means they believed they had the right to expand westward and they did! they stated with the 13 colonies and then they kept moving gaining different territories throughout the years

The answer i think is d