All mammals have

Options

A. Mammary gland
B. Diaphragm
C. Vertebrae
D. All of these

Answer

To answer the question "All mammals have," we need to analyze the given options and determine which features are universally present in all mammals.

### Step-by-Step Solution:

1. **Identify the Options**: The options provided are mammary glands, diaphragm, vertebrae, and possibly others. We need to evaluate each option to see if it is a characteristic of all mammals.

2. **Evaluate Mammary Glands**:
- Mammary glands are specialized glands that produce milk.
- All mammals possess mammary glands, which are essential for nursing their young.
- **Conclusion**: This option is correct.

3. **Evaluate Diaphragm**:
- The diaphragm is a muscular structure located below the lungs that plays a crucial role in respiration.
- It separates the thoracic cavity from the abdominal cavity and is present in all mammals.
- **Conclusion**: This option is also correct.

4. **Evaluate Vertebrae**:
- Vertebrae are the interlocking bones that form the spinal column.
- They provide support and protection for the spinal cord.
- All mammals have a vertebral column made up of vertebrae.
- **Conclusion**: This option is correct as well.

5. **Final Evaluation**:
- Since all the options (mammary glands, diaphragm, and vertebrae) are characteristics found in all mammals, the correct answer is "all of these."
- Therefore, the answer to the question is option 4: all of these.

### Final Answer:
All mammals have mammary glands, diaphragm, and vertebrae. Thus, the correct answer is **option 4: all of these**.