THE EARTH DAY

2. A poisonous form of oxygen
6. Able to continue over a period of time
8. Small pieces of rubbish that have been left lying on the ground in public places
9. The natural environment in which an animal or plant usually lives
11. The air, water, and land in or on which people, animals, and plants live
12. The process of getting rid of large amounts of rubbish by burying it, or a place where rubbish is buried
13. To make new furniture, objects, etc. out of old or used things or waste material
15. The relationships between the air, land, water, animals, plants, etc., usually of a particular area, or the scientific study of this
16. Decaying plant material that is added to soil to improve its quality
18. To keep and protect something from damage, change, or waste
19. To make an area or substance, usually air, water, or soil, dirty or harmful to people, animals, and plants, especially by adding harmful chemicals

1. Of or from the sun, or using the energy from the sun to produce electric power
2. Not using artificial chemicals in the growing of plants and animals for food and other products
3. The mixture of gases around the earth
4. The substances from factories, houses, etc. that go into the air
5. Renewable forms of energy can be produced as quickly as they are used
7. Not now existing
10. To sort and collect rubbish in order to treat it and produce useful materials that can be used again
14. Small pieces of rubbish that have been left lying on the ground in public places
17. To keep something as it is, especially in order to prevent it from decaying or being damaged or destroyed