Question

screen time after midnight most often harms health by: *
boosting deep sleep time
reducing rem and total sleep quality
improving morning focus
increasing hydration

Explanation:

Screen time after midnight, especially from devices emitting blue light, disrupts the sleep - wake cycle. This disruption affects the REM (Rapid Eye Movement) phase and overall sleep quality. “Boosting deep sleep time” is incorrect as screen time harms sleep, not boost deep sleep. “Improving morning focus” is wrong because poor sleep from screen time would reduce focus. “Increasing hydration” has no relation to screen time's effect on health. So the correct option is the one about reducing REM and total sleep quality.

Answer:

B. Reducing REM and total sleep quality