1. extinct - When something is completely gone and doesn't
return.
2. pollution - The process or act of defiling.
3. ozone - A type of oxygen that is produced by electricity and is in the air.
mostly after a thunderstorm.
4. endangered species - Specific species that is at risk for extinction due to
natural and human forces.
5. poacher - A person who trespasses, usually to hunt or fish illegally.
6. conservation - The act of preserving; to keep from being used up or lost.
7. evolution - The idea that all things living developed from very few simple
life forms through several physical changes.
8. smog - the contamination of smoke and fog in the air.
9. habitat - A specific dwelling place where an animal lives.
10. atmosphere - The specific gas that surrounds the earth.
11. insecticide - Something that eliminates insects.
12. biosphere - The area that surrounds the earth that may support life.
13. greenhouse effect - The retention of radiation from the sun into the
earth's atmosphere that creates a rise in the temperature of the earth's
surface.