Here's why:
* Run-on sentence: A sentence that joins two or more independent clauses without proper punctuation or conjunction.
* Independent clause: A complete thought that can stand alone as a sentence.
* Conjunction: A word that connects words, phrases, or clauses (e.g., and, but, or, so).
Here's an example of a run-on sentence:
> I went to the store I bought some milk.
This is a run-on because it combines two independent clauses without proper punctuation or a conjunction.
Here are some ways to fix the run-on:
* Use a period: I went to the store. I bought some milk.
* Use a comma and a conjunction: I went to the store, and I bought some milk.
* Use a semicolon: I went to the store; I bought some milk.
In summary: A conjunction is used to connect independent clauses, but in a run-on sentence, the clauses are incorrectly joined without proper punctuation or conjunctions.