The
video
shows
three
kinds
of
gases
that
are
necessary
to
keep
the
Earth
warm
;
they
are
____________________
____________________
,
____________________
and
____________________
____________________
.
If
these
gases
didn´t
exit
,
the
Earth
would
be
____________________
.
These
gases
trap
the
____________________
of
the
sun
and
keep
the
Earth
____________________
.
