CBSE Class 10 Science 2017 · Paper 31/3 · Question 6

Coal and petroleum are natural resources because they occur in nature and are not made by humans: they were formed by natural processes from the remains of plants and animals buried in the earth millions of years ago, and they are obtained from the earth for human use (as fuels and raw materials). Reason for using them judiciously: they are exhaustible (non-renewable). They take millions of years to form, so their stock is limited and will run out if they are used carelessly. (Burning them also pollutes the air with carbon dioxide and oxides of sulphur and nitrogen, a further reason to use them with care.)