A. birds prepare for breeding B. bird feathers differ from species C. birds shed and replace their feathers D. birds are affected by seasonal changes 参考答案:C 答案解析:全篇多次出现,也是最核心的一个词是molt,即“脱毛”。文章开篇就对该词做了解释: “Molting is one of the most involved processes of...a bir