Which of these statements is correct about the function of blood?

Options

A. It helps in transportation of respiratory gases.
B. It regulates body temperature.
C. It helps in transportation of waste products.
D. All the above

Explanation

### Step-by-Step Solution:

1. **Understanding the Functions of Blood**:
Blood has several critical functions in the body, which include transportation of gases, regulation of body temperature, and removal of waste products.

2. **Analyzing Each Statement**:
- **Statement 1**: "It helps in the transportation of respiratory gases."
- This statement is correct. Blood contains hemoglobin, a protein that carries oxygen from the lungs to the body's tissues and transports carbon dioxide back to the lungs for exhalation.

- **Statement 2**: "It regulates body temperature."
- This statement is also correct. Blood helps maintain a stable body temperature by distributing heat throughout the body and facilitating heat loss through the skin.

- **Statement 3**: "It helps in the transportation of waste products."
- This statement is correct as well. Blood transports waste products, such as urea, to the kidneys for excretion.

3. **Considering Additional Functions**:
- Blood also plays a role in clotting to prevent excessive blood loss when injuries occur.

4. **Conclusion**:
- Since all the statements provided are correct regarding the functions of blood, the correct answer is "All of the above."

### Final Answer:
The correct answer is **Option 4: All of the above**.