Read the sentence.

The Nile, a river that flows through Egypt, is home to crocodiles and hippopotamuses.

Which word or group of words is an appositive in the sentence?

river

a river that flows through Egypt

crocodiles and hippopotamuses

The Nile

The appositive is usually a group of words related to a noun, usually a subject, and describes it in more detail.

The appositive here is a river that flows through Egypt.

Another way of easily spotting an appositive is by looking for commas - if it is separated from the rest of the sentence by commas, it is likely to be an appositive.