a、b、c表示生物体内的三个生理过程，如图所示的三个过程中Y代表的物质分别是 ①

                                                       A peacock and a nightingale
     It was a fine day. A peacock was dancing happily in the forest. He began to __1__ suddenly because
 he saw a  nightingale __2__  in a tree. He said to the nightingale sadly, "You have a sweet __3__ , but I
 don't have."
     Just then the king of birds came. He asked, "Peacock, why are you so __4__ ? " the peacock said to
 __5__ , "I have such a beautiful body, but my voice is so bad that everyone will __6__  me."
     The king of birds said, "You don't __7__  to be sad. All things have their own strong points (优点) and
 weaknesses. For example, you have a beautiful body but don't have a sweet voice. A nightingale has a
 sweet voice, but he doesn't __8__ as beautiful as you. __9__  you should learn to live __10__  your
 weakness. Do you think it's right?