Which postulate of Dalton's atomic theory is the result of the law of conservation of mass? Options: 1) Atoms of different elements differ in every respect i.e., mass, size and chemical properties. 2) During chemical combination, atoms of different elements combine in small whole numbers to form compounds. 3) All the atoms of a given element are identical in every respect, having the same physical and chemical properties. 4) The relative number and types of atoms are constant in a given composition