What low-density substance mainly makes up earth's crust?

What is the depression formed by the impact of a meteorite called? What was the name of the ship that drilled holes in the sea floor? How many meters is the Kilimanjaro? How long does it actually take earth to travel around the sun? Do chlorofluorocarbons make the ozone layer thicker? What plant is a giant gas planet with bands of strips when it comes to size its number two it has bright rings? How is the frequency you hear different from that being produced by an approaching ambulance that you can see and hear as you drive down the road? Why does the number of species increase and decrease? What does the line if you can look into the seeds of time and say which grain will grow? What is 98.6 f in c? What body part benefits from iron? Why do tornadoes happen in Africa? What is a solid or semisolid amorphous compound obtained from some plants as an exudation? What natural cycle involves photosynthesis and cellular respiration? What Accounts for most of the carbon dioxide emissions for a country? What are the characteristics or properties of metamophic rock? Which metallic element atomic no. 83 soothes gastric ulcers? How many acres is Brookfield zoo? Why do cells in your body need to be specellized? What instruments are used in the song supermassive black hole?