Word form: It is expensive to ……… solar energy. (collective)

Word form
1. It is expensive to ……… solar energy. (collective)
2. Nuclear reactors ……… large amount of power. (provision)
3. The gasoline engines cause air ………. (pollute)
4. The ……… from the earth to the sun is too great for us to travel there. (distant)
5. ……… energy is not only plentiful and infinite but also clean and safe. (sun)