Yes, this is a run-on sentence. A run-on sentence occurs when two or more independent clauses are joined together without proper punctuation or conjunctions.
Step-by-step explanation:
Yes, this is a run-on sentence. A run-on sentence occurs when two or more independent clauses are joined together without proper punctuation or conjunctions. In the given sentence, 'The source of the Mississippi River is Lake Itasca in Minnesota' and 'it was formed by a melted glacier' are both independent clauses. To correct the run-on sentence, you can either separate the clauses into two separate sentences or join them with a coordinating conjunction like 'and' or 'but'.