21. The gradual rise in the Earth's temperature is known as ____.
A. greenhouse effect B. global warming C. ozone layer D. acid rain
22. The ____ that are produced by factories and cars are allowing more ____ from the sun to reach carth.
A. gases – radiation B. gases - light C. gas – light D. gas - radiation
23. As the Earth gets hotter, the Arctic and Antarctic ____ will slowly melt and the level of the oceans will rise.
A. snowballs B. avalanches C. ice caps D. icebergs
24. There will be ____, too. Some areas will become wetter while others will become much drier.
A. weather changes B. weather forecasts C. climatic changes D. climate changes
25. Thousands of acres of forest are being cut down every year and the ____ of many animals are being destroyed.
A. natural resources B. natural habitats C. ways of life D. living surroundings
26. Many of the world's largest cities are ____ and some are permanently covered by a ____.
A. heavily polluted - polluted cloud B. heavy pollution - polluted cloud
C. heavy pollution - cloud of pollution D. heavily polluted - cloud of pollution
27. Make sure your car runs on unleaded petrol and your home uses sources of ____ energy.
A. recycling B. reused C. renewable D. recyclable
28. Scientists have found holes in the ____, particularly over Antarctica.
A. ice caps B. polar ice C. ozone layer D. greenhouse
29. Greenpeace is an international group that protests against anything which is a ____ to the environment.
A. threat B. threaten C. threatening D. threatener
30. If government don't ____ global warming, more natural disasters will occur.
A. achieve B. promote C. discourage D. prevent
