1 Complete the missing words. Polar bears live in the Arctic. As a result of (1) g___ w___, this vast area of ice is melting fast and the polar bear's habitat is under threat. The polar bear is already an (2) e___ s___. If temperatures continue to increase at this rate, they could (3) b___ e___ Hunting and climate change are two causes, but tourism is also a threat. Long-distance travel isn't (4) e___ f___ and expeditions to the Arctic pollute and disturb the ecosystem. For many animals under threat, (5) w___ ___ have provided a solution. But the fact is that the polar bear can't survive in higher than (6) f___. So the whole planet needs to make an effort. It's up to us to stop (7) a___r___ and prevent our planet from overheating.