Although he stayed calm during the conversation, marco was angry as he left professor johnsen's office because he felt he had been treated unfairly. a short while later, marco snapped at a fellow student who asked if she could borrow his notes. which ego defense mechanism best accounts for marco's behavior toward the other student?

The answer is displacement. This is a defense mechanism whereby the mind substitutes either another point or another question for objectives felt in their unique shape to be unsafe or unsuitable. 
A term starting with Sigmund Freud, this works in the psyche unknowingly, its transference of feelings, thoughts, or wishes being regularly used to mollify uneasiness even with forceful or sexual driving forces.

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