Many researchers attribute the large number of physiological and behavioral similarities between birds and mammals, which have separate evolutionary histories, to endothermy (a thermoregulatory strategy whereby warm body temperature is maintained through internal heat sources). However, Farmer argues that parental care rather than endothermy is the key to understanding the similarities between mammals and birds. According to Farmer, while endothermy provides an explanation for a few similarities, such as the presence of body insulation, endothermy is just one characteristic among many related to parental care. The two purported advantages of endothermy that have been most frequently cited by researchers are an expanded range of inhabitable environments and the ability to sustain vigorous exercise. But metabolism has to increase substantially (at great energy cost) therefore conferring any significant thermoregulatory advantage in terms of the former, and there is no causal biological linkage to explain why endothermy would be essential to sustain exercise. Farmer argues instead that endothermy evolved as a means to control incubation temperature and that the ability to sustain exercise evolved separately, as a means to improve a parent’s ability to forage and provision its young.

　　1. The primary purpose of the passage is to

　　A. present a scientific theory that challenges a widely held theory

　　B. summarize the basis for a large body of scientific research

　　C. defend an established scientific theory in light of recent criticism

　　D. express skepticism about the results obtained by a particular researcher

　　E. compare the results of two particular scientific studies

　　2. Which of the following best characterizes the organization of the passage as a whole?

　　A. A position is noted, an alternative to that position is introduced, and then several points in support of the alternative are discussed.

　　B. A theory is discussed, an inconsistency within that theory is illustrated, and then a recommendation is made for further inquiry.

　　C. Certain research results are described, the significance of those results is explained, and then a novel interpretation of those results is summarized.

　　D. A question is posed, a possible answer to that question is suggested, and then evidence is provided to corroborate that answer.

　　E. A debate is outlined, contrasting viewpoints within the debate are discussed, and then one viewpoint is demonstrated to be correct.

　　3. According to the passage, Farmer concedes that endothermy provides an explanation for which of the following features shared by birds and mammals?

　　A. The ability to forage

　　B. The ability to sustain exercise

　　C. The instinct to care for offspring

　　D. Flexibility in habitat usage

　　E. Body insulation

　　答案：

　　A A E