3. How is the potential energy of any object released? What happens to this released energy? I

I believe for living things it is released as heat.  

but In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. Common types of potential energy include the gravitational potential energy of an object that depends on its mass and its distance from the center of mass of another object, the elastic potential energy of an extended spring, and the electric potential energy of an electric charge in an electric field.

Explanation:

hope that helps