Final answer:
When you join two independent clauses with a comma, it creates a comma splice, which is a grammatical error. To correctly join two independent clauses, you can use a coordinating conjunction along with a comma, or you can use a semicolon.
Step-by-step explanation:
When you take two independent clauses and join them with a comma, you create a comma splice, which is considered a grammatical error. Independent clauses are complete thoughts that can stand alone as sentences. To correctly join two independent clauses, you can use a coordinating conjunction (such as and, but, or) along with a comma, or you can use a semicolon.