Across
- 2. Power derived from physical or chemical resources especially to provide light and heat
- 4. A giant mass of ice that moves slowly down a valley or mountain
- 5. The surrounding air, water and land in which we live
- 6. The process of making air, water or land dirty and unstate
Down
- 1. To treat waste materials so they can be used again
- 3. The process of planting trees