While gasoline isn't the only fuel we use to transport ourselves, it is certainly the most widely used and the greatest source of pollution in our society today. Other fuels that help transport people include natural gas and ethanol. The energy we use every day comes from resources. Resources are broken up into two categories renewable and nonrenewable. Renewable resources are those that can be used or made over and over again from other resources - they are unlimited.
Wood is a renewable resource because more trees can be grown to make more wood.
Coal is an example of a nonrenewable resource because there is only so much of it on earth. Once we have mined it all, we will need to reuse it in order to have more for other uses. Sometimes resources are converted from one form to another to get the energy we need. For example, we turn crude oil into gasoline to power most of our cars. Gasoline a fuel which contains stored energy.