How Is Coal Formed?
How Is Coal Formed? Coal comes from plants that have been buried in the earth so long, they turned hard and black. Millions of years ago, much of the earth was swampy...
Read MoreHow Is Coal Formed? Coal comes from plants that have been buried in the earth so long, they turned hard and black. Millions of years ago, much of the earth was swampy...
Read MoreHow Do Cavities Form in Teeth? Our teeth are covered with a sticky, slimy substance plaque that enables decay producing germs to cling to them. Shortly after eating...
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