what is fossil fuels?

 Fossil fuel are those natural resources which are  Exhastibleand Non-renewable , which means that they take a long time to be formed and which again cannot be obtain except by natural process. They also help in our day to day lifelike in form of heat (coal)etc. . But since they are exhastible we need to use them carefully as the present consumption may lead to exhistentence of these resources. To save this resources we must use the alternate sources of energy.