题型分类：文章总结题

题干分析：选择概括性的正确选项。

选项分析：

A选项是第一段和第二段的重要信息。“Although play often resembles aggression, flight, or other purposeful activities,”对应第一段的“One of the problems in providing a clear definition of play is that it involves the same behaviors that take place in other circumstances – dominance, predation, competition, and real fighting.” “researchers do not agree on the reasons for and functions of play.”对应第二段的“Exactly why animals play is still a matter debated in the research literature, and the reasons may not be the same for every species that plays.”

D选项是第三段和第四段的重要信息。“Energy expenditure and security risks are some of the costs to animals of play behavior,”对应第三段“Therefore, it results in the loss of fuel or energy that might better be used for growth or for building up fat stores in a young animal.”以及“Another potential cost of this activity is greater exposure to predators since play is attention-getting behavior. Greater activity also increases the risk of injury in slipping or falling.”；“but the costs are not so great that they outweigh the long-term benefits of play to the species.”对应第四段“The benefits of play must outweigh the costs…”。

F选项是第四段至第六段的重要信息。“As experiments and observations have shown, animals that play at some stage of their development obtain neurological”对应第四段的“Some of the potential benefits relate directly to the healthy development of the brain and nervous system.”；“muscular”对应第五段的“Play also stimulates the development of the muscle tissues themselves and may provide the opportunity to practice those movements needed for survival.”；“or social benefits from the play behaviors.”对应第六段的“Play can also provide practice in social behaviors needed for courtship and mating.”

B选项中“because each animal species uses so few of the many available types of play behavior.”文中未提及“uses so few of the many available types…”。无中生有。

C选项中“too many young animals become victims of their natural predators while playing”，文中未提及too many，与原文描述不符。

E选项中“learn how to be both dominant and submissive”，文中没有说both，与原文描述不符。