if the same question i take in terms of car(human body) and ask why this car's at rest?
someone uttered combustion of fuel is not taking place, next one said engine is not running and even air fuel mixture is also not accomplished by carburetor,radiator went too hot.
No.
Everything is at its place. but to steer the wheel to run the car to fill the fuel and in unfavorable situations,even to push that car, a 'driver' is needed.
as car stops even when fuel is empty.but driver can fix the problem.
have to find that energy which get converted as the person dies(according to newtons 1st law energy can neither be created nor be destroyed)