Answer:
During the 1930s, extreme drought and high winds made life incredibly difficult in the Great Plains region of the United States.
Step-by-step explanation:
The topic sentence is the most important sentence in a paragraph. It sets the main hypothesis, the tone, and the general idea of the paragraph. In general terms the topic sentence is at the beginning of the paragraph and often, as in this case, it is the first sentence. As we can see in the extract, the text is giving information about the "Dust Bowl," the phenomenon in which extreme drought and high winds caused grave ecological and economic problems in the Great Plains region of the United States. All this idea is clearly summarized and introduced in the first sentence.