Environment

2. An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound.
6. The basic unit of a chemical element.
9. (verb: photosynthesize) The process by which green plants and some other organisms use sunlight to produce foods from carbon dioxide and water.
11. Scattered fragments, typically of trash or of something that has been destroyed. Space debris includes the wreckage of defunct satellites and spacecraft.
12. A group of similar organisms capable of producing offspring that can survive and reproduce.

1. A gas that makes up about 21 percent of the atmosphere. All animals and many microorganisms need oxygen to fuel their metabolism.
3. A portion of the light spectrum that is close to violet but invisible to the human eye.
4. The envelope of gases surrounding Earth or another planet.
5. dioxide (or CO2)A colorless, odorless gas produced by all animals when the oxygen they inhale reacts with the carbon-rich foods that they’ve eaten.
7. The field of science that deals with the composition, structure and properties of substances and how they interact with one another.
8. The second planet out from the Sun.
10. A device that generates an intense beam of coherent light of a single color. Lasers are used in drilling and cutting, alignment and guidance, in data storage and in surgery.