Over thirty thousand years ago,people from northern Asia   went to America.Today, we call these people Indians . The Indians went to America because the weather began to change.Northern Asia became very cold. Everything froze. They had to move or die. How did the first Indians go to America? They walked! Later Columbus found the New World in 1492.At first,only a few Europeans followed .They travelled to America in boats. For the next three hundred years, about 500,000 people went there. Then the number grew very quickly. From 1815 to 1915,over thirty-two million Europeans left their countries and went to the United States. The biggest groups were from Germany and Italy .These Europeans spoke many different languages.Most of them took almost no money.They went to America so that they could find a better life. Why did the Indians go to America? Because   _  .
northern Asia became very hot northern Asia became very cold they were interested in America they liked travelling
Question: Over thirty thousand years ago,people from northern Asia   went to America.Today, we call these people Indians . The Indians went to America because the weather began to change.Northern Asia became very cold. Everything froze. They had to move or die. How did the first Indians go to America? They walked! Later Columbus found the New World in 1492.At first,only a few Europeans followed .They travelled to America in boats. For the next three hundred years, about 500,000 people went there. Then the number grew very quickly. From 1815 to 1915,over thirty-two million Europeans left their countries and went to the United States. The biggest groups were from Germany and Italy .These Europeans spoke many different languages.Most of them took almost no money.They went to America so that they could find a better life. Why did the Indians go to America? Because   _  .
A. northern Asia became very hot
B. northern Asia became very cold
C. they were interested in America
D. they liked travelling
Answer: