When we talk about energy, the first thing that comes to our mind is ‘enthusiasm’. Isn’t it? In the same way things around us have ‘energy’ in them; in other words, they too have a lot of ‘fuel’ in them. But what if this energy vanished? Anything in the world wouldn’t work. And for these things to work, what are their energy sources? For humans, if it is food, what are the sources of energy for things? Let us study them below.