Here's why:
* Common Noun: Refers to a general class of things, not a specific individual or item. "Fuel" represents any substance used for burning to produce energy.
* Proper Noun: Refers to a specific person, place, or thing (e.g., John, New York, the Eiffel Tower).
* Collective Noun: Refers to a group of people or things (e.g., team, flock, herd).
Let me know if you have any other noun questions!