Which of the following is true about oxidation-reduction reactions?
One atom is oxidized and one is reduced

Both atoms are oxidized and reduced

The total number of electrons changes

One atom can be oxidized without one being reduced

B"hf and f-"  is the correct answer took the test on edgenuity and got it right     

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.