5. Catherine recently began working the night shift at her residence hall front desk from midnight until 8:00 AM. She is having difficulty staying awake at night and sleeping during the day because of...

5.
Catherine recently began working the night shift at her residence hall front desk from midnight until 8:00 AM. She is having difficulty staying awake at night and sleeping during the day because of disruption to her _____, already established for sleeping/waking.