<span>auditory
circulatory
respiratory
integumentary
muscular
reproductive</span>
Answer:
its circadian rhythm coordinated by pineal gland through melatonin hormone that it produces!!
The second one hope it helps
. You don't want to plateau. Adding variety to your workouts will keep your exercises from becoming ineffective. If you run at the same speed on the treadmill everyday for 20 minutes, your body will eventually hit a plateau
