Many
greenhouse
____________________
,
e
.
g
.
carbon
dioxide
,
methane
and
ozone
,
____________________
naturally
and
are
needed
to
create
the
____________________
____________________
that
keeps
the
Earth
warm
enough
to
____________________
human
life
.
However
,
the
use
of
fossil
fuels
,
e
.
g
.
oil
,
natural
gas
and
coal
,
has
produced
____________________
amounts
of
greenhouse
gases
,
and
the
result
is
____________________
____________________
:
an
increase
in
the
average
temperature
on
Earth
.
Of
the
15
warmest
years
on
____________________
,
14
have
occurred
since
2000
.
The
effects
of
____________________
change
can
already
be
seen
in
our
everyday
lives
.
Summers
are
getting
hotter
and
winters
are
getting
wetter
,
so
drought
and
____________________
are
becoming
more
common
.
With
it
,
animal
and
plant
life
is
____________________
?
some
species
will
disappear
altogether
?
and
certain
illnesses
,
e
.
g
.
hay
fever
,
asthma
and
skin
cancer
,
are
becoming
more
common
.
