In English, it is necessary to distinguish between singular and plural nouns.

He is good at distinguishing between good wine and bad wine.

She can make a subtle distinction between tea and coffee.

Your cooperation is needed for this project.

I need you.

A noun is one of the main elements of a sentence.

He can speak English fluently.

There are many words in English that are the same in singular and plural forms.

He thinks that war is a necessary evil.

Do you understand the necessity of this project?