Surface mining is the method of removing the overburden parts of the earth which are the earth and rocks. It also involves removal and loading out of the coal, and then placing back the collected earth back into a surface once again. It's also a method that uses equipment or explosives.
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Earth convection occurs at the mantle layer
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The movement of less dense material above the more dense material is called as convection. The mantle is the layer that lies between the core and the crust of the earth. The mantle is composed of rocks containing silicon, magnesium, oxygen, aluminium, iron and other minerals.
The heat energy of the core is transmitted to the rock in the lower mantle. This makes the rock with less temperature that lies in upper mantle to move down slowly. Now the rocks that are pushed up is eventually cooled and again pushed down by the hotter rock from the lower mantle. This is called as convection in earth’s mantle .
Answer:
C
Explanation:
Earth rotates once in about 24 hours with respect to the Sun, but once every 23 hours, 56 minutes, and 4 seconds with respect to other, distant, stars. Earth's rotation is slowing slightly with time; thus, a day was shorter in the past. This is due to the tidal effects the Moon has on Earth's rotation.
Active transport move molecules from low concentrations to high concentrations.
