A little boy is being pushed in a wagon by his mother. Suddenly, the little boy's mother stops to watch for cars before she crosses the street. The little boy's body continues to move forward in the stopped wagon until he tumbles out. The forward movement of the boy's body shows – * A) Newton's law of gravity.
B) Newton's law of inertia.
C) Newton's law of force and acceleration.
D) Newton's law of action-reaction.