Complex sentence: In humans the average oral temperature is, though it varies among individuals, as well as cycling regularly through the day, as controlled by one's circadian rhythms with the lowest temperature occurring about two hours before one normally wakes up.
Split into simpler sentences: In humans the average oral temperature is, though it varies among individuals. Temperatures cycle regularly up and down through the day, as controlled by one's circadian rhythms with the lowest temperature occurring about two hours before one normally wakes up.