I'm not sure what type of fuel you're talking about. If you mean fossil fuel then kerosene has the highest density of all of the things you listed.
Answer:
easy
Explanation:
In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.