Dalton's experiments advanced our understanding of the atom withouta. carefully observing and measuring events. b.discovering the internal structure of the atom. c.examining the ratios of elements involved in chemical reactions. d.testing a hypothesis.

B: Discovering the internal structure of the atom.

Explanation:

Dalton’s experiments with gases marked the beginning of the modern era of chemistry. The hypotheses about the nature of matter on which Dalton’s atomic theory is based can be

summarized as follows:

Elements are composed of extremely small particles called atoms. All atoms of a given element are identical, having the same size, mass, and  chemical properties. The atoms of one element are different from the atoms of  all other elements. Compounds are composed of atoms of more than one element. In any compound,  the ratio of the numbers of atoms of any two of the elements present is either an  integer or a simple fraction. A chemical reaction involves only the separation, combination, or rearrangement  of atoms; it does not result in their creation or destruction.

Dalton made no attempt to describe the structure or composition  of atom —he had no idea what an atom is really like. But he did realize that the  different properties shown by elements such as hydrogen and oxygen can be explained  by assuming that hydrogen atoms are not the same as oxygen atoms.

The answer would be

Rn in the right answer