[covidSurvivor19]

I'm not denying the 2nd law, but metabolism is more complicated than just heat or mechanical work. One example, the process by which the body transforms ammonia into urea, requires energy. Not 100% sure of the details but some of this energy might be captured chemically, not sure if urea has a higher (free energy? I don't remember the exact term). Furthermore with this example, since urine is hyperosmotic, the body has to do a process against normal ion/water diffusion, in order to excrete minerals and not excessive water. This osmotic pressure, contains some potential energy.