Heat is referred to energy that is transferred from one body to another as a result of difference in temperature
The picture above shows that Deserts are very hot during the day. Plants and animals living in the desert need special adaptations to survive in the harsh environment.
An object decreases its temperature by releasing energy in the form of heat to its surroundings. And an object increases its temperature by gaining energy in the form of heat from its surroundings. The higher the temperature of an object is, the greater the tendency of that object to transfer heat. A substance may absorb heat without an increase in temperature by changing from one physical state to another, from solid to liquid (melting) from solid to vapour (suppression), from liquid to vapour (boiling), or from one solid form to another (crystalline transition).
As stated heat is the transfer of energy and the transfer of energy always takes place from the region of the higher temperature to the region of the lower temperature. Heat is the energy in flow due to the difference in temperature.