The arteries differ from veins in having :

Options

A. Arteries consist of three distinct layers , which are thin and collapsible whereas veins consist of three distinct layers, which are rigid , thicker and highly muscular.
B. Veins consist of three distinct layers, which are thin and collapsible whereas arteries consist of three distinct layers , which are rigid , thicker and highly muscular.
C. Veins consist of two distinct layers, which are thick and collapsible whereas arteries consist of three distinct layers , which are rigid , thicker and highly muscular.
D. Arteries consist of three distinct layers , which are thin and muscular whereas veins consist of three distinct layers, which are rigid , thicker and highly vascular.

Answer

To solve the question "The arteries differ from veins in having:", we will analyze the differences between arteries and veins step by step.

### Step-by-Step Solution:

1. **Understanding the Basic Functions**:
- Arteries and veins are both blood vessels but serve different functions in the circulatory system.
- Arteries carry oxygenated (pure) blood away from the heart to various parts of the body.
- Veins carry deoxygenated (impure) blood back to the heart.

**Hint**: Remember the primary function of arteries and veins in terms of oxygenation.

2. **Structural Differences**:
- Arteries have three distinct layers in their walls:
- **Tunica intima**: The innermost layer.
- **Tunica media**: The middle layer, which is thick and muscular.
- **Tunica externa**: The outer layer.
- Veins also have three layers, but they are thinner and less muscular compared to arteries.

**Hint**: Focus on the composition and thickness of the layers in arteries versus veins.

3. **Location in the Body**:
- Arteries are located deeper within the body, providing protection and support.
- Veins are often located closer to the surface of the skin.

**Hint**: Consider the anatomical positioning of arteries and veins.

4. **Color and Oxygen Content**:
- The blood in arteries is bright red due to high oxygen content.
- The blood in veins appears darker (often described as blue) due to lower oxygen content and higher carbon dioxide levels.

**Hint**: Think about how the oxygen content affects the color of the blood in arteries and veins.

5. **Pressure Differences**:
- Blood pressure in arteries is high because they carry blood pumped directly from the heart.
- Blood pressure in veins is lower, as it relies on the movement of blood back to the heart through various mechanisms, including muscle contractions and one-way valves.

**Hint**: Recall how the heart's pumping action influences blood pressure in arteries and veins.

6. **Final Comparison**:
- Based on the above differences, we can conclude that arteries are thicker, more muscular, and carry oxygenated blood, while veins are thinner, less muscular, and carry deoxygenated blood.

### Conclusion:
The correct answer to the question "The arteries differ from veins in having:" is that arteries have thicker, more muscular walls compared to veins.

### Answer:
**Option 2**: Arteries have three distinct layers which are thick and muscular, while veins have thinner and collapsible layers.