All
living
things
are
____________________
up
of
tiny
units
____________________
cells
.
The
cells
are
____________________
by
a
covering
____________________
a
membrane
.
The
membrane
controls
what
moves
in
and
out
of
the
cell
.
Cells
need
many
kinds
of
materials
in
order
to
____________________
.
They
must
have
water
,
oxygen
,
glucose
(
sugar
)
,
sodium
,
potassium
and
a
variety
of
other
minerals
.
The
body
____________________
to
have
a
delivery
system
to
get
these
materials
where
they
need
to
go
.
____________________
____________________
,
every
cell
produces
waste
materials
that
it
needs
____________________
____________________
____________________
____________________
.
The
body
____________________
to
have
a
method
of
waste
collection
and
____________________
.
Like
a
fl
eet
of
trucks
form
a
transport
system
to
the
pick
up
and
deliver
goods
in
the
world
,
the
body
____________________
a
transport
system
,
too
.
There
are
two
types
of
transport
:
active
transport
,
and
passive
transport
.
Passive
transport
is
easiest
for
the
cells
because
they
don't
need
to
use
any
energy
to
make
it
happen
.
Diffusion
____________________
the
simplest
and
most
common
form
of
passive
transport
.
During
the
diffusion
process
,
tiny
particles
of
the
materials
that
need
to
be
delivered
to
the
cells
are
spread
through
either
a
gas
,
like
oxygen
,
or
a
liquid
,
like
water
.
Areas
with
high
concentrations
of
the
materials
slowly
diffuse
them
to
areas
of
low
concentration
of
the
materials
.
Osmosis
is
a
unique
form
of
passive
transport
that
____________________
water
____________________
pass
through
the
cell
membrane
but
keeps
most
other
materials
out
.
