A mid ocean ridge is made by a divergent boundary. The mid-ocean ridges of the world are connected and form a single global mid-oceanic ridge system that is part of every ocean. The mid-oceanic ridge system is the longest mountain range in the world. The continuous mountain range is 65,000 km (40,400 mi) long.
Circadian rhythms are important in determining human sleep patterns. The body's master clock, or SCN, controls the production of melatonin, a hormone that makes you sleepy. Since it is located just above the optic nerves, which relay information from the eyes to the brain, the SCN receives information about incoming light.
As such, sleep, in particular REM sleep, has been suggested to play an important role in the elaboration of neuronal circuitry during development . The circuitry controlling sleep and wakefulness appears to mature early in development , although cycling between states is more frequent in younger animals (111, 645).