Why is molecularity applicable only for elementary reactions,while order is applicable for both elementary and complex reactions?

(N/A) An elementary reaction is a single-step process where the molecularity is defined as the number of reacting species taking part in the collision.
In contrast,a complex reaction occurs through a series of elementary steps.
Since each step in a complex reaction may have a different number of molecules involved,the molecularity of the overall complex reaction is not defined or is considered meaningless.
However,the order of a reaction is an experimentally determined quantity that depends on the rate-determining step (the slowest step) of the mechanism,making it applicable to both elementary and complex reactions.