if in the measurement of the distance between two points on a sheet the uncertainty is equal to 2mm, when the Inter termination interval is valid

Answerboth technicians (a) and (b);

Is there any opitions? if you have the periodic table, the noble gases are 8a family, the halogen are the 7a family, and the nonmetal are  carbon, nitrogen, phosphorus, oxygen, sulfur, selenium, fluorine, chlorine, bromine, iodine and astatine.

One answer could be erosion