Which of the following contributed most to increased settlement
of the Great Plains?

Im pretty sure the discovery of precious metals i hope this helps you :)

Explanation:

a series of federal land grants.

Explanation:

Congress passed a law allowing people to claim public land and convert it to private property through homesteading.

The Great Plains is the broad expanse of flat land that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada

hope it helps

mark me brainliest pls

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.