Globulins contained in human blood plasma are primarily involved in

Options

A. Defence mechanisms of body
B. Osmotic balanace of body fluids
C. Oxygen transport in the blood
D. Clotting of blood

Explanation

### Step-by-Step Solution:

1. **Understanding Globulins**: Globulins are a group of proteins found in blood plasma. They play crucial roles in various physiological processes.

2. **Identifying Functions of Globulins**: The primary functions of globulins include:
- **Defense Mechanism**: Certain globulins, known as immunoglobulins, are involved in the immune response. They help in identifying and neutralizing pathogens like bacteria and viruses.
- **Osmotic Balance**: Globulins, along with albumins, help maintain osmotic pressure in the blood, which is essential for fluid balance in the body.

3. **Eliminating Incorrect Options**:
- **Oxygen Transport**: This function is primarily carried out by hemoglobin, which is not a globulin present in plasma but rather a protein found in red blood cells.
- **Blood Clotting**: Blood clotting involves specific clotting factors and proteins, which are not classified as globulins.

4. **Conclusion**: Based on the functions identified, globulins in human blood plasma are primarily involved in:
- **Defense Mechanism** (via immunoglobulins).
- **Osmotic Balance** (along with albumins).

5. **Final Answer**: Therefore, the correct answer to the question is that globulins are primarily involved in both the defense mechanism and maintaining osmotic balance in the body.