Answer:
Answer would be C because combustion does the process of heat. Oxygen is a reactant in a combination reaction, which always produces energy in the form of heat and light. Carbon burns in the presence of oxygen to give carbon dioxide.
External force.
Air resistance, friction, grass rubbing on a rolling ball, etc.
If there is no external force on a moving object, it keeps going.
Forever !
Convection is the rise of hot air and the drop of cold air due to a large amount of molecules being moved usually in gas form.\
Hope this helps!
Many ways for example they look up related things and study them or they can test it and see what happens