单项选择题

The author refers to "external mechanisms" primarily in order to

A．suggest that a biochemical analysis of dinosaur thermoregulation might be a waste of time
B．suggest that other means than warm-bloodedness may account for evidence of dinosaur thermoregulation
C．explain why scientists are interested in looking for an absence of seasonal variations in oxygen 18 traces
D．suggest that metabolic rates, not warm-bloodedness, may have been the key factor in certain dinosaurs' survival
E． imply that other factors beside temperature may dictate the ratio of oxygen isotopes
<上一题 目录 下一题>
热门 试题

单项选择题
The author's primary purpose is to
A．answer a theoretical question in the field of dinosaur thermoregulation
B．discuss the current state of research in the field of dinosaur thermoregulation
C．resolve a dispute in the field of dinosaur thermoregulation research
D．predict a future crisis in the field of dinosaur thermoregulation research
E． suggest some of the possible benefits of a technique in dinosaur thermoregulation research
单项选择题
According to the passage, the most severe problem currently facing scientists in conclusively determining whether certain dinosaurs were warm-blooded is
A．proving that thermoregulation is the primary means by which metabolic rates are influenced
B．developing a way of distinguishing between oxygen 18 and oxygen 16
C．showing that an absence of seasonal variation in oxygen 16 implies a constant internal temperature
D．finding a sample of dinosaur tissue which has survived 65 million years in a relatively intact form
E． determining which species of dinosaurs were most likely to be warm-blooded, and focusing research there
相关试题