What would be the BEST way to represent this data that illustrates change in average temperature over time? A) a data table of all data collected for the five years B) a bar graph comparing each year's average temperature C) a map of the state with the average temperatures written at each site D) a line graph showing the average change in temperature over five years

Adozen is 1221/12 = 1.751.75 x 12 = 21therefore, 1.75 is the answer.

And a) oxygen i believe

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.