Coal is a non renewable source of energy, once consumed cannot be recovered. Therefore the quantity of coal is reduced with its continuous usage throughout in the world. On the other hand solar energy is a renewable source of energy and it has to do nothing with the quantity of consumption. So we can say that replacing non renewable sources of energy such as coal with renewable sources of energy that is solar energy can make the coal supply last longer.
Definition - the state or quality of something being humid. Two things that increase humidity are 1) more water vapor in the air (more moisture) 2) lower temperature
