A scientist is studying the apparent position of the moon in the sky over the course of one month he notices that the apparent position of the moon changes everyday when viewed from the same position at the exact time

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.