Section 1.4 of the textbook describes circadian rhythms. You may have noticed that you have natural highs and lows throughout the day. Thinking about your own 90-minute cycle and how it may relate to yourself and learning, how would you prepare yourself for taking a big test in your course/class at the end of the day? If you need more information, consider reviewing the Circadian Rhythms Fact Sheet (Links to an external site.) from the National Institutes of Health or the open-access Journal of Circadian Rhythms (Links to an external site.).