There are 4 non-REM stages and REM sleep.
As of 2008, the American Society of Sleep Medicine combined the stages three and four. So now there are only 3 stages
The main stages are expansion, prosperity, contraction and recession
3
Stage 1 is light sleep where you drift in and out of sleep and can be awakened easily. In this stage, the eyes move slowly and muscle activity slows. During this stage, many people experience sudden muscle contractions preceded by a sensation of falling.In stage 2, eye movement stops and brain waves become slower with only an occasional burst of rapid brain waves. When a person enters stage 3, extremely slow brain waves called delta waves are interspersed with smaller, faster waves. In stage 4, the brain produces delta waves almost exclusively. Stages 3 and 4 are referred to as deep sleep, and it is very difficult to wake someone from them. In deep sleep, there is no eye movement or muscle activity. This is when some children experience bedwetting, sleepwalking or night terrors.In the REM period, breathing becomes more rapid, irregular and shallow, eyes jerk rapidly and limb muscles are temporarily paralyzed. Brain waves during this stage increase to levels experienced when a person is awake.
How many kilojoules are used during 8 hours of sleep?
Scientists hypothesize that there are two main stages to the formation of Pangaea: the assembly stage, during which the continents were moving closer together, and the breakup stage, when Pangaea began to split into separate continents.
The eukaryotic cell cycle consists of four main stages: G1 (Gap 1), S (Synthesis), G2 (Gap 2), and M (Mitosis). During these stages, the cell grows, copies its DNA, prepares for division, and divides to form two daughter cells.
Cicadas typically spend around 2 to 17 years underground in their nymph stage before emerging as adults. This period of dormancy is known as their "sleep," during which they feed on plant roots and undergo stages of growth and development.
YOU CAN NOT SLEEP AT WORK!!You will get fired!!!
Many tigers sleep during the day much that do are white and black tigers, though i have never seen a black and white tiger sleep during the day but many white and black tigers do.
Stage 1