Answer:
The answer is letter a, Paleo-Indians.
Step-by-step explanation:
The Paleo-Indians were the first migrants in the United States. Their migration happened 12,000 years ago at the end of the last Ice Age (Pleistocene glaciation). They are considered to be the ancestors of the Native Americans.
Paleo-Indians- They are also called Paleoamericans. There are several theories regarding their migration. Some claim that they used a land-and-ice-bridge (Beringia land bridge) in order to cross. This bridge was formed between northeastern Siberia and western Alaska. This means that the animals were also able to cross going to the USA. Others claim that they used primitive boats in order to cross the Pacific coast.
The earliest human activity in America is proven by the stone tools that were found. These tools were made of stones and were used to hunt. They served as arrowheads and spear points.
Additional Information:
For the other choices, let me explain when they migrated into the USA.
Latin Americans- They migrated into the USA in the 1920s.
Europeans- The United States experienced a huge number of European migrants in the country from 1880 to 1920. The country was deemed to have a good economic opportunity, which is the main reason why people flock to the place. The Europeans had two reasons to migrate: to have a good economic life and to flee from religious persecution. Many Europeans experienced famine in their places, so it greatly affected their economic condition. They were also persecuted by the church. They wanted to attain the freedom to express their faith. Many of the church leaders also violated or didn't follow the biblical writings.
Spanish- Spain migrated into the USA in the 15th century. Their primary reason was to search for resources such as gold and silver.