Riverside High School's Test Scores Have Been Dropping for Several

Multiple Choice

Riverside High School's test scores have been dropping for several years since they instituted a start time before the middle and elementary schools. The test scores for the same students in middle school were all in line with state standards, and many are not now. The school board has recently learned about the delayed phase preference. With this knowledge, they have decided to delay start times that will greatly affect the students' ______ and hopefully test scores.

A) amount of sleep
B) cortisol levels
C) substance use
D) HPG axis