The author"s view of the difference between boys and girls is based on （）.

A．If the genes can be found, scientists can study many new ways to cure illnesses.
B．The scientists have made great progress in connecting the genes with the cancers.
C．Many medical companies show great interest in drawing the human genome map.
D．The United States began the Genes Study early in the 19th century.

A．no one had ever known the desert before the miners
B．it"s still not easy to travel across the desert
C．people can find gas-stations, cafes and hotels in the desert
D．people have changed the natural sight of the desert