It depends.
The most common source is chemical energy, in the shape of Gasoline or Diesel refined from petroleum, a fossil fuel.
You can have electric energy too, but as long as that electricity is coming from the combustion of fossil fuels this isn't really much of an improvement.
Then there are biofuel (also chemical energy) cars as well, which basically means that there's some sort of plant material that's been processed into something combustible that can be fed into an engine.
CARS , VEHICALS ,ELECTRICTY FUELS.
Hydrocarbon fuel.
Fossil fuels
Gasoline is a Mechanical energy because gasoline can make cars move and cars are moving things.
The source of energy that is used in chemosynthesis is the chemicals.
Light energy is used . Sun is the source
The source of energy used by mitochondria is ATP.
Ultimately the Sun. Cars run on fossil fuels which is made from the remains of organism that lived and grew on the planet in the past. These living organisms depended on sunlight as the source of their energy.
The source of energy in stoves is HEAT ENERGY
fule fossile is the most used energy source
Fossil fuels
mechanical energy you hobo