What best describes how energy changes form in a car’s engine

Simplification can be done as:

1) initially we have chemical energy or potential energy in the fuel (it also can be electric energy in some cars)

2) the fuel is combusted, generating thermal energy and a change in pressure that moves pistons, so there is also mechanical energy at this moment.

3) the mechanical energy is used to move the car, so we again have mechanical energy, and some energy is dissipated as heat (this is why a car starts to gain temperature as it travels for a given time) so we again have some thermal energy, some that come from the combustion and some that comes from the motion itself (like friction in inner parts and such)

For the electrical cases, the electrical energy is transformed into mechanical energy and thermal energy directly, there is no combustion.

in most common fires, oxygen is needed for an oxidation reaction to takes place. the combination of oxygen with any element as fuel can create fire and combustion will occur especially if wood, light materials and other combustible things are combine with oxygen.