Question

which is a run - on sentence? the furnace heats the apartment. vivian and ellie will work on the problem, they will find a solution.

Explanation:

A run - on sentence combines two or more independent clauses without proper punctuation or a coordinating conjunction. "Vivian and Ellie will work on the problem" and "they will find a solution" are independent clauses joined only by a comma, which is incorrect. The first sentence "The furnace heats the apartment." is a simple, correctly - structured sentence.

Answer:

Vivian and Ellie will work on the problem, they will find a solution.