Which of these helps to increase friction?

Options

A. Ball bearings
B. Oil and grease
C. Treads or grooves
D. Polishing and waxing

Answer

To determine which of the options helps to increase friction, we need to analyze each option based on how they affect the nature of surfaces in contact.

### Step-by-Step Solution:

1. **Understanding Friction**: Friction is a contact force that arises when two surfaces interact. It depends on the nature of the surfaces in contact, specifically their roughness or smoothness.

2. **Analyzing the Options**:
- **Ball Bearings**: These are used to reduce friction by allowing surfaces to roll over each other instead of sliding. Therefore, they do not increase friction.
- **Oil and Grease**: These substances create a smooth layer between surfaces, reducing friction. Thus, they do not increase friction.
- **Treads and Grooves**: These features are designed to increase the surface area and roughness of a surface, which enhances friction. They create more interlocking between surfaces, leading to higher friction.
- **Polishing and Waxing**: These processes smooth out surfaces, which reduces friction. Therefore, they do not increase friction.

3. **Conclusion**: Among the options provided, only treads and grooves help to increase friction. Therefore, the correct answer is **Treads and Grooves**.

### Final Answer:
**Treads and Grooves** help to increase friction.

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