When water decomposes into oxygen and hydrogen, the mass

a. remains constant.
b. decreases.
c. varies according the number of hydrogen and oxygen molecules that form.
d. increases.

When water decomposes into oxygen and hydrogen, the mass "Remains Constant" as according to Law of Conservation of mass, mass can neither be created not destroyed,.

In short, Your Answer would be Option A

Hope this helps!

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.