A
fertilised
ovum
is
called
a
____________________
.
This
is
the
first
stage
in
pregnancy
.
It
travels
to
the
____________________
where
the
cells
continue
to
divide
and
multiply
until
they
become
an
____________________
.
Then
,
it
fixes
itself
to
the
lining
of
the
uterus
.
After
nine
weeks
the
organs
have
started
to
develop
and
the
embryo
becomes
a
____________________
,
which
is
protected
by
____________________
fluid
and
receives
nutrients
and
oxygen
through
the
____________________
.
Pregnancy
lasts
about
280
days
.
