____________________
are
the
building
blocks
of
all
living
things
.
The
human
body
contains
hundred
of
different
types
of
cells
that
each
serve
a
different
____________________
.
Each
cell
has
____________________
that
allow
it
to
work
effectively
within
living
things
.
Nerve
cells
are
often
known
as
____________________
.
Their
function
is
to
carry
____________________
signals
around
the
body
.
These
signals
carry
____________________
Epithelial
cells
are
cells
that
cover
the
____________________
of
your
body
,
such
as
your
skin
,
blood
vessels
,
urinary
tract
,
or
organs
.
They
serve
as
a
____________________
between
the
inside
and
outside
of
your
body
,
and
protect
it
from
viruses
.
They
are
like
the
____________________
of
plumbing
pipes
or
containers
.
Muscle
cells
contract
or
____________________
to
be
able
to
____________________
body
parts
.
They
also
contain
a
lot
more
____________________
than
other
cells
to
be
able
to
produce
additional
____________________
to
help
change
their
length
.
Muscle
cells
are
like
____________________
Connective
cells
for
the
most
part
____________________
different
body
parts
together
.
They're
____________________
like
spindly
fibers
help
it
to
stick
to
other
cells
.
These
are
like
____________________
that
holds
things
together
.
