1. 1. A 2. B 3. B 4. A 5. 21% 6. mass, volume, density and pressure 7. air molecules push in all direction (not just down, but also up and to the sides.) 8. inches of mercury and millibars 9. C 10. F 11. G 12. D 13. A 14. E 15. B

2. 1. THERMOSPHERE 2. MESOSPHERE 3. STRATOSPHERE 4. TROPOSPHERE 5. 80 km 6. THERMOSPHERE 7. STRATOSPHERE & THERMOSPHERE 8. DECREASES 9. TROPOSPHERE 10. STRATOSPHERE 11. TRUE 12. MESOSPHERE 13. THERMOSPHERE 14. TRUE

3. 1. Answers may vary…  Troposphere- weather occurs  Stratosphere- ozone layer filters out UV-Rays  Mesosphere- most meteors burn up  Thermosphere- hottest temperatures (split into ionosphere and exosphere) 2. A meteor. It is debris that burns up as it passes through the mesosphere 3. Gases that glow because they become electrically charged in the ionosphere (lower thermosphere) 4. The air is very thin (very low density) and does not absorb much energy from the sun.