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

She can make a subtle distinction between tea and coffee.

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

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.

Do you understand the necessity of this project?

That information is unnecessary.