Final answer:
Dalton's work was based on experimental evidence, while Democritus' was purely theoretical. Dalton's work emphasized the idea of atoms having different properties, while Democritus' focused on their uniformity.
Step-by-step explanation:
Dalton's work was based on experimental evidence, while Democritus' was purely theoretical. John Dalton formulated his atomic theory by focusing on experimental results, studying the weights of various elements and compounds. Democritus, on the other hand, reasoned that changes occur when atoms in an object were recombined in different ways, without experimental evidence. Dalton's work emphasized the idea of atoms having different properties, while Democritus' focused on their uniformity. Therefore, option c is the correct answer.