Fill in the correct words.

1. There aren't any wild wolves in Britain anymore. They became ... 250 years ago. 2. When the polar ice caps ... , the sea level rises. 3. Carbon dioxide is a ... gas. 4. A lot of animals are losing their natural habitat and dying; the number of animals under ... is increasing all the time.
5. We should all try to reduce our carbon ... . 6. Car ... produce gases that surround the Earth. 7. Changing weather ... threaten a lot of animals with extinction. 8. Acid rain can even ... the stone we use for buildings.