GRE Reading Comprehension: Maggoosh-GRE阅读Maggoosh - YREGM5EVRS07I21TM

Which of the following does the passage imply regarding birds? A. They possess certain traits that are not common to all ectotherms. B. They required more food than a similarly-sized mammal. C. Over time they might have undergone a change in how they regulate body temperature.