题目内容：

    DNA analysis has revealed family relationships between more than 10 generations of Stone Age people at megalithic (巨石的) tombs in Ireland and Sweden.

The evidence suggests that megaliths, prehistoric large stone structures, sometimes acted as graves for family groups in northwestern Europe thousands of years ago. The latest findings throw new light on the origins and social structure of the groups that built megaliths in this region—a history that has long been hidden in mystery.

For their study, the international team of researchers analyzed the genomes—the complete set of genetic material in a cell—of 24 Stone Age individuals from five megalithic burial sites in Ireland, Scotland and Gotland, a large Swedish island in the Baltic Sea.

This analysis showed that many of the individuals buried at each megalith, who all lived between  3,800 B.C. and 2,600 B.C.,  according  to  radiocarbon-dating  of  their  remains,  were closely related via family ties.

The results also showed that the individuals buried at the megaliths were related to Neolithic farmers in northern and western Europe but genetically distinct from other hunter-gatherers. This was particularly noticeable at the Ansarve site on the island of Gotland.

“The people buried in the Ansarve tomb are remarkably different on a genetic level compared to the individuals dug out from hunter-gather contexts, showing that the burial tradition in this megalithic tomb, which lasted for over 700 years, was performed by distinct groups with roots in the European Neolithic expansion,” Magdalena Fraser, co-first author from Uppsala University, said in the statement.

1.What’s the significance of the new findings?

A. It reveals the family ties between people in Ireland and Sweden.

B. It implies that many people buried in the tombs were closely related.

C. It indicates the long-hidden mystery concerning DNA analysis.

D. It suggests that the megaliths became tombs thousands of years ago.

2.How did the researchers reach their findings?

A. By interviewing individuals. B. By travelling to different regions.

C. By analyzing genes. D. By studying the burial sites.

3.Which is true according to the latest findings?

A. Some people buried in the tombs were related to farmers.

B. Few people buried in the tombs were genetically different.

C. All the people buried at megaliths had family relationships.

D. People buried in the Ansarve tomb were dug out 700 years later.

4.What’s the main idea of this passage?

A. Megaliths served as tombs thousands of years ago.

B. People buried at the megaliths were recently analyzed.

C. Latest findings shed light on a mystery about burials.

D. Stone-Age people in Ireland and Sweden had close ties.