The statement that 'heat cannot flow by itself from a body at a lower temperature to a body at a higher temperature', is known as

The Second Law of Thermodynamics is one of three Laws of Thermodynamics. The Second Law of Thermodynamics is commonly known as the Law of Increased Entropy. While quantity remains the same (First Law), the quality of matter/energy deteriorates gradually over time. How so? Usable energy is inevitably used for productivity, growth and repair. In the process, usable energy is converted into unusable energy. Thus, usable energy is irretrievably lost in the form of unusable energy.