What is the simple subject in this sentence?

These homes are built up from the bottom of the pond.

a. these
b. homes
c. pond

What are built up?

homes

Right.

homes

The simple subject of a sentence is the main noun or pronoun that the sentence is about. To identify the simple subject, you can ask yourself, "Who or what is performing the action or being described?"

In the given sentence, "These homes are built up from the bottom of the pond," the simple subject is "homes." It is the main noun in the sentence that the sentence is about because it is the thing being built up from the bottom of the pond. Therefore, the answer is b. homes.