Which of the following accurately describes "atomic theory"?

Atomic theory, as originally proposed by early scientists like John Dalton, posits that atoms are the fundamental building blocks of matter and that they are indivisible units. This concept implies that atoms themselves cannot be broken down into smaller components through chemical means, portraying them as the smallest identifiable units of an element. The understanding that atoms exist as individual units of matter laid the groundwork for modern chemistry, shaping our comprehension of how substances interact and combine.

The other statements explore different aspects of matter but do not accurately represent the core of atomic theory. The idea that atoms are created in reactions is inconsistent with the classical view of atomic theory, as it suggests a transformation of matter that is more aligned with nuclear reactions rather than chemical reactions. The assertion that all substances can exist as solid, liquid, or gas pertains to the states of matter but does not address the structure or composition of matter at the atomic level. Lastly, the notion that matter exists in multiple forms also describes the physical states of matter without delving into the foundational concepts of atomic theory. Thus, the emphasis on atoms being the smallest indivisible units truly captures the essence of atomic theory.