Marlene has been tense and anxious during her professors’ lectures, and it is causing her to have a difficult time at college. she has been better lately because she distracts herself by counting the number of times her professors say "the" during their lectures. marlene’s "counting" suggest she is experiencing:

Panic attacks

Explanation:

Anxiety is the way the human body reacts to stress and there are five major types of anxiety disorders; Generalized Anxiety Disorder, Obsessive-Compulsive Disorder, Panic Disorder , Post-Traumatic Stress disorder and Social Phobia (or social anxiety disorder). Marlene suffers from Panic Disorder which leads to panic attacks and her counting is a coping mechanism which helps her to calm down as it helps her to focus greatly.

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