Question

Why carbon instead of oxygen is considere for the caclulation of atomic mass unit?

Answer 1

because first scientist notice that with the help of oxygen we calculate every atom mass but it .....prove wrong by other scientists then.. notice that their is other also element in the atmosphere with the help of that we calculate the atomic mass of any atom and this element is carbon

Answer 2

Because atomic mass of oxygen is not a whole no. it is less than 16 but atomic mass of carbon is exactly 12 so it was convenient for reference