Final answer:
The force acting on the box being pulled along a horizontal surface is the frictional force.
Step-by-step explanation:
The force acting on the 10 kg box being pulled along a horizontal surface is the frictional force.
Frictional force is the force that opposes motion between two surfaces in contact with each other.
In this case, as the box is being pulled along the horizontal surface, the frictional force acts in the opposite direction of the motion exerted on the box, preventing it from sliding.