Here's why:
* Clause: A clause is a group of words that contains a subject and a verb and expresses a complete thought.
* Punctuation: The punctuation of a clause is important because it signals whether the clause is independent (can stand alone as a sentence) or dependent (needs to be attached to an independent clause to make sense).
Examples:
* Independent clause: "The cat sat on the mat."
* Dependent clause: "Because the cat was sleepy."
Let me know if you have any other questions!