Final answer:
Eunice is using the displacement ego defense mechanism to manage her stress by directing her frustrations towards her roommate instead of the actual sources of her anxiety.
Step-by-step explanation:
When Eunice yells at her roommate after experiencing a series of unfortunate events, she is using the displacement defense mechanism. This mechanism involves transferring her emotional response from the appropriate, threatening targets—such as her broken car or poor exam grade—to a less threatening one, like her roommate. In this way, Eunice is unconsciously attempting to manage her stress and frustration without addressing the actual sources of those feelings.