What happened during the agricultural expansion in the southern Great Plains？A．People impr

What happened during the agricultural expansion in the southern Great Plains？

A．People improved the soil by planting wheat.

B．Raising cattle and other livestock became less common.

C．Most of the landowners became farmers.

D．Much of the grassland was destroyed.

此题为多项选择题。请帮忙给出正确答案和分析，谢谢！