Coal is formed when swamplands are buried by sediment. the added weight creates heat and pressure that converts plants to coal.
a. true
b. false

The statement above is true.

Coal used to be the primary source of energy of our civilizations, almost all our technology used coal back then. Train, cooking stove, machine in the factory, etc.

Now, it's used to make coke ( the building material, not the drinks). pencil, and in village usually to replace firewood.

The correct answer is kettles.