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:

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.

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