An automobile engine transforms chemical energy into mechanical energy, and mechanical energy is the sum of Kinetic Energy and Potential Energy. Given these facts, what works by summing kinetic energy and potential energy among the following options:
- Riding a bike
 - transportation technology
 - adding heat
 - an automobile engine
 - circulatory systems
 - a hydraulic system
 - Thyroid-stimulating hormone
 - heterotrophs


 

    an automobile engine     