hi quick questions on subject complements

example:

A group of whales is a pod.

is the subject group of whales, or just whales and then what is group? pod is the complement, right?

Thanks!

Here is the Grammar Monster entry for subject complement.

A group of whales is a pod.

The subject is 'A group of whales'.
The principal word that governs the verb is 'group', not 'whales'.
The subject complement is 'pod'.


Word order plays a role in identifying the subject complement. In the sentence:

A pod is a group of whales.

The subject is 'pod', and the subject complement is 'a group of whales'.