People
need
____________________
or
more
hours
of
sleep
.
Teenagers
have
difficulty
____________________
asleep
until
late
at
night
.
____________________
are
those
who
are
more
active
during
night
time
.
Larks
,
on
the
other
hand
,
prefer
____________________
____________________
during
early
morning
hours
.
Experts
on
insomnia
are
opposed
to
____________________
____________________
as
this
may
disrupt
sleep
patterns
at
night
.
We
____________________
sleep
for
the
brain
to
get
a
chance
to
rebuild
memories
and
associate
these
with
previously
learned
things
.
Drinking
alcohol
,
taking
nicotine
or
doing
mentally
intense
activities
at
night
should
be
avoided
if
you
have
trouble
____________________
.
Some
individuals
try
to
stay
away
from
caffeine
for
fear
____________________
____________________
awake
all
night
.
When
you're
napping
,
it's
possible
____________________
____________________
when
the
caffeine
starts
taking
effect
.