Why are morphological and syntactic criteria more accurate criteria for determining word class ?

The syntactic criteria for word classes are based on what words a given word occurs with and the types of phrase in which a given word occurs whereas Looking at the "shape of a word" to determine the class the word belongs to can be called a morphological criterion. There are two branches of morphology include the study of the breaking apart (the analytic side) and the reassembling (the synthetic side) of words; to wit, inflectional morphology concerns the breaking apart of words into their parts, such as how suffixes make different verb forms.At least three criteria are used in defining syntactic categories: The type of meaning it expresses. The type of affixes it takes. The structure in which it occurs.Other examples include table, kind, and jump. Another type is function morphemes, which indicate relationships within a language. Conjunctions, pronouns, demonstratives, articles, and prepositions are all function morphemes. Examples include and, those, an, and through.

idk how you get this but its hard for me : c