Classes :

This one way to refer to classes, and is perhaps more formal than using a plural

The tigger is threatened with extinction

National Groups

The spanish sleep more time than the French

Other groups

The Beatles

Unique objects.When use the when we know that there is only one of a particular thing :

The moon , the sun, the world, the North Pole

But note that there are other moon in universes for example

this planet has a small moon

The same applies to the following things when we refer to them in a general way

the weather, the climate, the human race, the future, the past, the sea, the sky, the wind , the atmosphere, the pubic

(Devamini Okuyun…)