Which of the following events contributed to the Dust Bowl?
Railroads stopped building lines across the
West.
The population of the Great Plains grew,
increasing the amount of land being used for
agriculture.
Farmers reduced the number of acres they
plowed each year.

it's B

Explanation:

The population of the Great Plains grew, increasing the amount of land being used for agriculture.

the monroe doctrine is the best known u.s. policy toward the western hemisphere. buried in a routine annual message delivered to congress by president james monroe in december 1823, the doctrine warns european nations that the united states would not tolerate further colonization or puppet monarchs.