1. The center of the earth is known as the   Crust   Atmosphere   Core   Hydrosphere   Hint Half-n-half Clue   2. Which of the following elements is a chemical constituent of sand particles?   Silicon   Iron   Carbon   Sodium   Half-n-half Clue   3. The surface of earth is mainly covered with   Mountains   Land   Oceans   Ice   Half-n-half Clue   4. Gasoline is a non-renewable source of energy.   True   False   5. Stalactites and stalagmites consist of deposits of   Sodium Bicarbonate   Calcium Carbonate   Magnesium Carbonate   Silica   Half-n-half Clue   6. What is caused by the slight tilt of the earths axis?   Tides   Day and Night   Seasons   Earthquakes   Half-n-half Clue   7. What is the name given to molten rocks that are erupted by a volcano?   Slate   Lava   Marble   Firestone   Half-n-half Clue