From 2004 to 2008, coal production in the United States increased from 1,094.3 million tons to 1,171.8 million tons. Rapid coal extraction (mining) can cause the depletion of natural coal deposits. Why is it important to conserve coal? Responses It is difficult to extract from the ground. It is difficult to extract from the ground. It cannot be replaced quickly once it is used up.
A) It cannot be replaced quickly once it is used up.
B) It gives the smallest amount of energy when it is burned.
C)It gives the smallest amount of energy when it is burned.
D) It is found in larger quantities in the earth than other fossil fuels.