Have you ever watched a cat when he
is asleep? If you have, you probably noticed that sometimes the cat opens his
eyes, and his eyes begin to move very quickly. But even though his eyes are
open , the cat cannot see anything while this is happening because he is still
asleep. The same thing happens to all animals when they are sleeping, and it
even happens to people. We humans do not normally open our eyes while we are
asleep, but we all have these short periods of rapid eye movement. Why does
this happen?
Until
recently , everyone believed that REM ( rapid eye movement)sleep was somehow
involved with dreams --that
is , with the pictures and stories we see in our heads while we are
asleep. The theory was that REM sleep helps our brain to process information
that it gets during the day. That made sense. Researchers have known since the
1950s that if you wake up some people who are having rapid eye movements, they
will always tell you they were dreaming. But for one scientist , this theory
did not make enough sense.
David
Maurice, of New York's Columbia University, discovered that some animals get
twice as much REM sleep as human beings. And babies who have not yet been born
get more than eight hours a day. Does an unborn child have so much information
to process every day? Probably not. So if information is not the reason for
REM, What is the reason?
The
eye is just like every other part of our body. It needs oxygen. Oxygen is
carried to the back of the eye by blood. From there, it spreads to the cornea through a liquid called aqueous humor. ( The
cornea is the window at the front of the eye.) When we are awake and our eyes
are open and looking at things, their constant movement helps to spread oxygen.
When we are asleep, we have nothing to look at., but we still need eye movement
to help deliver oxygen to our corneas. That is the reason for REM sleep , says
David Maurice. Without it , our corneas would die, and we would wake up blind.
1. The main idea of paragraph 2
is:
a. People believe
that REM of a sleeping person means he is dreaming.
b. Cats have REM when they sleep
c. Babies dream when they sleep
d. Our Eyes need oxygen when we sleep
2 . David Maurice's theory says that
REM sleep is necessary because_________.
a) it helps us look at things
b) helps brain to process information
c) it delivers oxygen to our corneas.
d) it happens to all animals
3.What is aqueous humor?
a) It is a kind of blood.
b) It is part of the cornea
c) It is a gas similar to oxygen.
d) It is a liquid through which oxygen
spreads to the cornea.
4.The underlined word “ there”
in the last paragraph refers to ________.
a)
the blood b) our body
c) the back of the eye d) the cornea
5 .What is the passage talking about?
a) REM is very important for all human beings
and animals.
b)REM helps us process information.
c)Animals have more rapid eye movement
than humans.
d) Unborn babies have the highest number of rapid eye movements.
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