The plural noun is a collective noun that refers to multiple singular nouns working together. However, the singular noun is a single abstract noun.
For example, the plural noun is "children" whereas the singular noun is "cat".
When referring to a plural noun, you use a plural verb. However, when referring to a singular noun, you use a singular verb.
It's all about subject-verb agreement! Don't get it twisted, or you'll get it wrong!