Final answer:
In the sentence 'Whales are the creatures of open sea', 'Whales' is the subject and 'are the creatures of open sea' is the predicate.
Step-by-step explanation:
In the sentence 'Whales are the creatures of open sea', you would circle 'Whales' as the subject and underline 'are the creatures of open sea' as the predicate.
Generally, the subject in a sentence is the entity doing the action or being described, and the predicate tells us what the subject is doing or what it is like. In this case, 'Whales' is the subject because they are what the sentence is about, and 'are the creatures of open sea' is the predicate because it tells us something about the whales.
Learn more about Subject and Predicate