21. When 50 ml water is added to 20 ml sugar and mixed thoroughly until the sugar dissolves,
what happens to the volume of the resulting mixture?
a. The volume of the resulting mixture is added to the sum of the volume of the unmixed sugar
and water
b. the volume of the resulting mixture is equal to the volume of the unmixed sugar and water
c. the volume of the resulting mixture is less than the sum of the volume of the unmixed sugar
and water
d. the volume of the resulting mixture is more than the sum of the volume of the unmixed sugar
and water​