题目内容：

    Stone tools and pieces of animal bone from about 16,600 years ago are the earliest evidence yet of human beings in the New World, scientists say.

The objects were found in the western United States. They were recovered from an archaeological site called Cooper Ferry on the Salmon River near the town of Cottonwood Idaho. Scientists used radiocarbon dating methods to find out how old these artifacts are.

The scientists say people lived in or passed through the area when ice covered large parts of North America. That period of time is known as Earth's Ice Age. During the period, big mammals like camels lived in North America. Loren D avis is an anthropology (人类学) professor at Oregon State University. He led the team of scientists working at Cooper's Ferry.

“The Cooper's Ferry site is the earliest radiocarbon-dated archaeological evidence in the Americas.” Davis said. The researchers said the artifacts suggest that people first lived in the area between 16,600 and 15,300 years ago and returned to live there many times after that.

Scientists say humans first appeared in Africa about 300,000 years ago and later spread throughout the world. There has been much scientific debate about when humans first entered the Americas. They are believed to have crossed into North America at a time when Siberia and Alaska were connected by land.

The new findings support the assumption that the first human migration into the Americas traveled down the pacific coast instead of an inland path. Davis said. “The Columbia river would provide the first Americans their first route to interior lands south of the continental ice sheet.”

The researchers noted details of some of the sharp objects that would have been used for hunting. These artifacts appear similar to those found in northern Japan from a somewhat earlier date. Davis said. “We assume that this may signal a cultural connection between early peoples who lived around the northern Pacific Rim.” “Traditional technological ideas spread from northeastern Asia into North America at the end of the last glacial period,” he added.

1.What do the “artifacts” in paragraph 4 refer to?

A.The migrants traveling into the North America.

B.The objects found in Cooper's Ferry on the Salmon River.

C.Stone tools and animal bones from about 300,000 years ago.

D.The camels living in north America during the earth's Ice Age.

2.It can be inferred from paragraphs 5-7 that ________.

A.migrants possibly traveled deep into North America through the Columbia

B.North America has long been considered the source of human civilization

C.there existed no cultural links between early peoples around the world

D.experts have agreed on when humans first entered the Americas

3.What is the best title for the text?

A.The Artifacts Recovered from an Archaeological Site in Africa

B.The Spreading of Ancient Technology between Early Settlers

C.The Benefits of Radiocarbon Dating Method

D.The First Human Migration into the Americas