why do i need sleepDoes anyone know why we need to sleep?

Okay so I am taking this psychology class at my local community college, and we have to do a project for out final.
We have to make a hypothesis on any psychological subject (i chose sleep), conduct an expriment and prove or disprove you hypothesis.
If anyone here can help me, tell me anykind of information you know about sleep, and why we sleep, and if we need sleep, that would really help alot.
Every creature needs to rest. Giraffes, little babies, elephants, dogs, cats, kids, koala bears, grandparents, moms, dads, and hippos in the jungle - they all sleep! Just like eating, sleep is necessary for survival.

Sleep gives your body a rest and allows it to prepare for the next day. It's like giving your body a mini-vacation. Sleep also giveswhy do i need sleep your brain a chance to sort things out. Scientists aren't exactly sure what kinds of organizing your brain does while you sleep, but they think that sleep may be the time when the brain sorts and stores information, replaces chemicals, and solves problems.

The amount of sleep a person needs depends a lot on his or her age. Babies sleep a lot - about 14 to 15 hours a day! But many older people only need about 7 or 8 hours of sleep each night. Most kids between the ages of 5 and 12 years old are somewhere in between, needing 10 to 11 hours of sleep. Some kids might need more and some need less. It depends on the kid.

Skipping one night's sleep makes a person cranky and clumsy. After missing two nights of sleep, a person will have problems thinking awhy do i need sleepnd doing things; his or her brain and body can't do their normal tasks nearly as well. After five nights without sleep, a person will hallucinate (this means seeing things that aren't actually there). Eventually, it becomes impossible for the brain to give its directions to the rest of the body without sleep - the brain needs to spend time in bed and catch its ZZZs!
-Sleep appears necessary for our nervous systems to work properly.
-Sleep is also the time when the body does most of its repair work; muscle tissue is rebuilt and restored.
-Sleep is also a time for restoring mental energy.
the brain regroups and organizes and the body (organs) etc. get time to slow metabolism
Cos the mind needs to rest.