How was the idea of Manifest Destiny brought about by nationalism?

Nationalism, or the belief that the United States was the most superior nation in the world, mostly drove the movement known as Manifest Destiny. Manifest Destiny was the belief that Americans had a God-given and ordained right to rule North America from the Atlantic Ocean to the Pacific Ocean.

the answer should be monarchy

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.