Among the organs of the body that are rich in mature T-cells and B-cells are:

Options

A. Liver and gallbladder
B. Spleen and lymph nodes
C. Brain and spinal cord
D. Small and large intestine

Answer

To determine which organs of the body are rich in mature T-cells and B-cells, we can analyze the options provided and their functions:

1. **Liver and Gallbladder**:
- The liver is primarily involved in the production of bile, which aids in digestion. The gallbladder stores bile. However, these organs are not primarily associated with the immune response or the presence of mature T-cells and B-cells.

2. **Spleen and Lymph Nodes**:
- The spleen is an organ that filters blood and is involved in the immune response. It contains a high concentration of lymphocytes, including both T-cells and B-cells.
- Lymph nodes are small, bean-shaped structures that filter lymph fluid and are also rich in lymphocytes, including T-cells and B-cells. They play a crucial role in the immune system by responding to pathogens.

3. **Brain and Spinal Cord**:
- These organs make up the central nervous system and are primarily involved in processing and transmitting information throughout the body. They do not play a significant role in the immune response or contain mature T-cells and B-cells.

4. **Small and Large Intestines**:
- These organs are primarily involved in digestion and nutrient absorption. They do have some immune functions, but they are not the main sites for mature T-cells and B-cells.

Based on this analysis, the organs that are rich in mature T-cells and B-cells are:

**Correct Answer: Spleen and Lymph Nodes.**