In embryonic stage erythrocytes develop from

Options

A. bone marrow
B. liver and kidney
C. spleen and kidney
D. liver and spleen

Answer

To answer the question "In embryonic stage erythrocytes develop from," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Erythrocytes**:
- Erythrocytes are also known as red blood cells (RBCs). They are crucial for transporting oxygen throughout the body.

2. **Process of Formation**:
- The formation of erythrocytes occurs through a process called erythropoiesis, which is a part of a broader process known as hematopoiesis.

3. **Initial Site of Hematopoiesis**:
- During the embryonic stage, hematopoiesis begins in the yolk sac. This is the first site where embryonic RBCs are formed.

4. **Transition to Hepatic Erythropoiesis**:
- After the first trimester of embryonic development, the site of erythropoiesis shifts to the liver, a process referred to as hepatic erythropoiesis.

5. **Final Site of Erythropoiesis**:
- By the fourth trimester, the production of erythrocytes transitions to the bone marrow, which becomes the primary site of RBC formation.

6. **Conclusion**:
- Therefore, during the embryonic stage, erythrocytes develop initially from the yolk sac, then from the liver, and finally from the bone marrow.

### Final Answer:
Erythrocytes develop from the yolk sac initially, then from the liver during the embryonic stage.