Answer:
This is what I found. Please rewrite this in your own words before writing it down for your homework. This was someone else's answer.
The Northern Plains weren'`t so badly affected, but the drought, dust, and agricultural decline were felt there as well. The agricultural devastation helped to lengthen the Great Depression, whose effects were felt worldwide.
They could place the cup under a large tree because the tree can provide shade from the sun, which will help cool the water down.