Approximately what percentage of the weight of the human body is water?

The average for male adults is about 60% and an female adult is around 50% depending on weight , age , and height 

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.

Answer earth,water,fire and air;