How do you use Newton's first law of motion to explain what would happen to a rolling marble if no outside force, such as friction, acted on it?
It would keep rolling unless it is stopped by an unbalanced external force.
This is in accordance with the Newton's first law of motion.
According to the first law of motion a body at rest tends to be at rest and a body in motion tends to be in the state of motion until and unless some external force acts on it.
The property of an object to stay at the same state is known as inertia. The rolling marble will not stop it's motion until and unless some external force acts on the system due it's property of inertia only. But if an external force is applied on the system then this applied force will be capable of changing the state of the body.