xPlate tectonics : The theory supported by a wide range of evidence that considers the Earth's crust and upper mantle to be composed of several large, thin, relatively rigid plates that move relative to one another.
In the spring of 2010, the eruption of a volcano called Eyjafjallajökull in Iceland cancelled many flights in Europe. Eyjafjallajökull is a glaciovolcano, which means it's a volcano that is covered by...Read more