We use collective nouns to refer to groups of people, animals, or objects.
I saw a flock of birds flying across the river.
The jury was in an isolated room as it deliberated.
The actor wanted to thank the crew for all their hard work.
We hiked up the range of mountains to the east of the city.
Collective nouns can be singular or plural. They are singular when we think of the group as a single unit, rather than separate individuals. This affects the determiners and verbs that go with the noun, as well as the pronouns that refer to it. In American English, it is common for speakers to treat all collective nouns as singular.
The committee is working on organising all sportive events this season.
The prideof lions is moving closer to the village so there is an elevated risk of attacks.
We planted a hedge of bushes to divide our land.
Collective nouns are plural when we think of the individuals that form the group.