Scientists at Harvard University and Bates College find female chimpanzees (黑猩猩) appear to

Scientists at Harvard University and Bates College find female chimpanzees (黑猩猩) appear to treat sticks as dolls, carrying them around until they have children of their own. Young males engage in such behavior much less frequently.
The new work by Sonya M. Kahlenberg and Richard W. Wrangham, described this week in the journal Current Biology, provides the first evidence of a wild non­human species playing with dolls, as well as the first known sex difference in a wild animal’s choice of playthings.
The two researchers say their work adds to a growing body of evidence that human children are probably born with their own ideas of how they want to behave, rather than simply mirroring other girls who play with dolls and boys who play with trucks. Doll play among humans could have its origins in object—carrying by earlier apes (猿类), they say, suggesting that toy selection is probably not due entirely to socialization.
“In humans, there are obvious sex differences in children’s toy play, and these are remarkably similar across cultures,” says Kahlenberg. “While socialization by elders and peers has been the primary explanation, our work suggests that biology may also have an important role to play in activity preferences.”
In 14 years of data on chimpanzee behavior at the Kibale National Park in Uganda, Kahlenberg and Wrangham counted more than 100 examples of stick­carrying. Some young chimpanzees carried sticks into the nest to sleep with them and on one occasion built a separate nest for the stick. “We have seen juveniles occasionally carrying sticks for many years, and because they sometimes treated them rather like dolls, we wanted to know if in general this behavior tended to represent something like playing with dolls,” says Wrangham, a Professor at Harvard. “If the doll hypothesis (假设) was right, we thought that females should carry sticks more than males do, and that the chimpanzees should stop carrying sticks when they had their first child. We have now watched enough young chimpanzees to prove both points.”
【小题1】What does a female chimpanzee do with sticks?A．She gives them to her child to play with.B．She treats them as dolls.C．She makes useful tools from them.D．She treats them as weapons.【小题2】 What causes the different toy selection of chimpanzees, according to the passage?A．Sex difference.B．Socialization.C．Environment. D．Cultural difference.【小题3】We can infer from the fourth paragraph that     .A．socialization has nothing to do with human’s choice of playthingsB．sex difference is the only factor in human’s choice of playthingsC．the biology factor may also influence toy choiceD．people choose different toys in different cultures【小题4】It can be concluded from the passage that     .A．both humans and chimpanzees choose their playthings due to sex differenceB．different factors cause humans and chimpanzees to choose different playthingsC．only female chimpanzees have playthingsD．chimpanzees usually choose playthings for their childrenB