Concept:Friction is a force that opposes motion between two surfaces in contact. Making a surface rough increases friction, which helps prevent slipping.Explanation:Soles of shoes are treaded to create a rough surface. This increases the frictional force between the shoe and the ground. Higher friction provides better grip and reduces the chance of slipping, especially on wet or smooth surfaces. Similarly, vehicle tyres have treads to improve traction and prevent skidding. Without treads, the sole would be smooth, leading to less friction and a higher risk of falls. Thus, treads are not primarily for protection or longevity, but to enhance friction.Answer:C. To increase friction