Why do the blood vessels in the toucan's bill shrink?

Can someone pretty me with this ? it’s urgent.compare the three theories of emotion. here are the three theories of emotion. cannon-bard theory of emotion: the belief that both psychological arousal and emotional experience are produced stimultaneously ( at the same time) by the same nerve stimulus. james-lange theory of emotion: the belief that emotional experience is a reaction to bodily events occurring as a result of an external situation. ( “ i feel sad because i am crying.) schachter-singer theory of emotion: the belief that emotions are jointly determined by a nonspecific kind of psychological (bodily function) arousal and its interpretation, based on environmental ( natural surroundings) cues. which of these theories makes most sense to you? why. your response should be written using proper english spelling and grammar. and it needs to be 10 complete sentences.

Which of the following does not make up ground substance of connective tissue? hyaluronic acid elastic fibers glycosaminoglycan proteoglycan

Which of these is one of the nitrogenous bases in dna? a. proline b. leucine c. glycine d. thymine