Question: Explain this in an easy way to understand: According to the First Law of Thermodynamics, energy cannot be created or destroyed, only changed in form (p. 10). This is also known as the principle of conservation of energy. In a biological system, this energy change is often referred to as the change in enthalpy (p. 10). For an exothermic reaction, the change in enthalpy is: Less than 0 (triangle H < 0). Need Assignment Help?