What does tryptophan bind to when it is present in e. coli?

Brad was almost hit by a speeding truck as he crossed the street. his heart began to race, and he felt extremely afraid as he jumped out of the way in just enough time to avoid the truck. a psychologist who supports the theory of emotion would claim that based on the arousal brad experienced, he appraised the situation and then labeled his racing heart as fear. a. james-lange b. cannon-bard c. schachter two-factor d. evolutionary