What is consists of all words that tell whom or what a sentence about?

The part of a sentence that consists of all words that tell whom or what a sentence is about is called the subject.

Here's a breakdown:

* Subject: The person, place, thing, or idea that the sentence is about. It is the main focus of the sentence.

* Predicate: The part of the sentence that tells what the subject does or is.

For example:

Sentence: The cat sat on the mat.

Subject: The cat

Predicate: sat on the mat.

The subject "The cat" is what the sentence is about. The predicate "sat on the mat" tells us what the cat did.