Bone marrow takes part in

Options

A. Controlling blood pressure
B. As haemopoietic tissue
C. Assisting kidneys
D. Assisting liver.

Answer

### Step-by-Step Solution:

1. **Definition of Bone Marrow**:
- Bone marrow is a semi-solid tissue found within the spongy or cancellous portions of bones.

2. **Location in Birds and Mammals**:
- In birds and mammals, bone marrow is primarily located in the spongy structures of bones.

3. **Primary Function**:
- The main function of bone marrow is to serve as the primary site for the production of new blood cells.

4. **Process of Blood Cell Production**:
- The process of producing new blood cells is known as hematopoiesis. This includes the formation of red blood cells (RBCs), white blood cells, and platelets.

5. **Composition of Bone Marrow**:
- Bone marrow is composed of hematopoietic tissue, which includes supportive stromal cells that assist in the production of blood cells.

6. **Conclusion**:
- Therefore, bone marrow plays a crucial role in hematopoiesis, making it an essential component in the production of blood cells.