Which best describes how combustion works?
a)it breaks and forms bonds of fuel to release thermal energy.
b)it breaks and forms bonds of fuel to release chemical energy.
c) it breaks and forms bonds of coolant to release thermal energy.
d)it breaks and forms bonds of coolant to release chemical energy.

A) It breaks and forms bonds of fuel to release thermal energy.

Explanation:

Chemical energy is the energy stored in the bonds of molecules.

Thermal energy is the energy possessed by a body by virtue of its temperature.

Combustion is a chemical reaction in which a fuel is burnt in the presence of oxygen to form carbon dioxide, water and heat.

Thus the chemical energy stored in the bonds of reactants is converted to thermal energy and heat is released in the combustion reaction.