1. Which of the following is not a constituent of the atmosphere?   Carbon Dioxide   Aluminum   Oxygen   Nitrogen   Hint Half-n-half Clue   2. Air is   An Element   A Mixture   An Alloy   A Compound   Half-n-half Clue   3. The lower, dense region of the atmosphere is known as   Ionosphere   Troposphere   Stratosphere   Hydrosphere   Half-n-half Clue   4. When we breathe which of the following gases do we use?   Hydrogen   Oxygen   Helium   Carbon Dioxide   Half-n-half Clue   5. A barometer is used for measuring   Humidity   Annual Rainfall   Temperature   Atmospheric Pressure   Half-n-half Clue   6. A hygroscopic substance is one which   Releases water   Releases air   Absorbs water   Absorbs air   Half-n-half Clue   7. Dry ice is   Any Frozen Liquid   Ice with salt added   Very Cold Ice   Solid Carbon Dioxide   Half-n-half Clue