Fill in the gaps using the given verbs.

1 The use of cars and planes greatly ... CO2 emissions.
2 I don't think genetically modified crops ... the quality of food.
3 It is impossible to make new paper without ... trees.
4 A power station near my home ... most of the electricity in the country.
5 Building roads often means that wildlife habitats are ... .
6 The amount of oxygen in the air has ... in recent years.