Pollution

3. the study of the relationships between organisms and their environment
6. composed of three oxygen atoms; odorless toxic gas
7. the presence or introduction of something into the environment that has harmful or poisonous effects
8. water that has already been used
12. build up of nutrients in bodies of water
13. used to destroy insects that are harmful to plants
15. matter organisms need to survive
16. a symbiotic relationship in which both organisms benefit

1. water that runs over land and picks up chemicals and pollutants along the way
2. source a type of pollution that comes from many sources
4. preventing wasteful use of a resource
5. a symbiotic relationship in which one organism benefits and the other is unaffected
9. a substance added to soil or land to increase its fertility
10. source pollution that can be traced back to a specific source
11. the gradual destruction and wearing away of something
12. the surroundings or conditions in which a person, animal, or plant lives
13. a symbiotic relationship in which one organism benefits and the other is harmed
14. a large wave that usually occurs in groups of 3