Final answer:
Skid-resistant rungs on ladders are important for safety reasons because they provide a better grip, reducing the risk of slipping and falling.
Step-by-step explanation:
In physics, the skid resistance of a surface is determined by the coefficient of friction between the surface and the object in contact with it. When it comes to ladders, having skid-resistant rungs is crucial for safety reasons. Skid-resistant rungs provide a better grip for the person using the ladder, reducing the risk of slipping and falling.