Environmental science

3. A natural fuel such as coal or gas, formed in the geological past from the remains of living organisms.
4. The emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles which cause ionization.
5. The production and discharge of something, especially gas or radiation.
7. A colorless, odorless gas produced by burning carbon and organic compounds and by respiration.
10. A glass building in which plants are grown that need protection from cold weather.

1. The action of clearing a wide area of trees
2. The process of making an area more urban.
6. Radiant energy emitted by the sun
8. A nonrenewable energy source.
9. The mixture of gases surrounding the Earth or other celestial body, held in place by gravity