Question

Is heat really necessary for us?what are its merits and demerits? Can heat won't harm us?

Answer 1

Yes.
Heat is a necessary thing for us
Sun is the majour source of heat and it is one of the important source of energies to the human being
For the proper functioning of human body organs,heat is necessary
But there are many advantages and disadvantages
heat is required for cooking food,for plants and animals,as a source of energy etc.
but heat is responsible for energy losses in our body,
and also energy losses in machines.
Heat is harmfull to us only when it is affecting more than a limit
only overflow of heat can harm us otherwise it is not