Which of the following postulates of John Dalton's modern atomic theory, published in 1800, is now known to be incorrect?

a. All atoms of a particular element are identical.
b. All matter is composed of tiny particles called atoms.
c. Atoms cannot be created or destroyed during chemical reactions.
d. Chemical compounds are combinations of elements in fixed ratios.
e. Atoms of different elements are different in some fundamental way(s).