Dr. Leonard Hofstader and Dr. Sheldon Cooper are the other two.
I believe that Howard Wolowitz is the only engineer.
Answer:
Large farms and cattle ranches cover much of the Great Plains. In fact, it is some of the best farmland in the world. Wheat is an important crop, because wheat can grow well even without much rainfall. Large areas of the Great Plains, like this land in Texas, are also used for grazing cattle.
Explanation:
Cars became popular in 20th century. I think this is the right answer.
Reconstruction lasted from 1863 to 1877, reconstruction abolished slavery and the communist. Reconstruction made the newly freed slaves have rights.
