Across
- 2. a group of gases that surrounds our planet.
- 6. a brown haze that develops in sunny, populated cities.
- 7. harmful substances that are in the air, water, or soil.
- 8. a system of symbols.
Down
- 1. a form of oxygen with three oxygen atoms in each molecule.
- 3. the peninsula that forms the southern part of Greece.
- 4. have great self-encouragement and will to do your very best.
- 5. vapor an invisible gas form, not steam.
- 6. a civilization that lived on the eastern Mediterranean coast and influenced Greek writing system.
- 7. to continue to never give up in big, difficult challenges.