1.) When a man is engaged to continuous exercise or work, not only his muscles are working but also there is increase in the rate of respiration too. This accelerated rate of respiration and heartbeat provides more oxygen and food to the body. So all the organs and organ systems work in coordination.
2.) I'm sorry that I don't know the answer to your question. The one which I know, I have already written.
It will be different according to how each of them is easily warmed up when using thermal energy. Water heats at 100 celsius and all the other solutions have slightly different boiling points
