In which of the following pairs the two items mean one and the same thing?

Options

A. Malleus -Anvil
B. SA node -Pace maker
C. Leucocytes -Lymphocytes
D. Haemophilia -Blood cancer

Answer

To solve the question, we need to identify which pair of items means the same thing. Let's analyze each option step by step.

### Step-by-Step Solution:

1. **Option A: Malleus and Anvil**
- Malleus is one of the three small bones in the middle ear, also known as the hammer.
- Anvil refers to another small bone in the middle ear, known as the incus.
- **Conclusion:** Malleus and Anvil are different bones. This pair does not mean the same thing.

2. **Option B: SA Node and Pacemaker**
- The SA node (sinoatrial node) is a group of cells located in the right atrium of the heart.
- It is responsible for generating electrical impulses that initiate the heartbeat, hence it is often referred to as the pacemaker of the heart.
- **Conclusion:** SA Node and Pacemaker refer to the same function in the heart. This pair means the same thing.

3. **Option C: Leukocytes and Lymphocytes**
- Leukocytes is a general term for white blood cells (WBCs), which are part of the immune system.
- Lymphocytes are a specific type of leukocyte that plays a significant role in the immune response.
- **Conclusion:** While related, leukocytes and lymphocytes are not the same; lymphocytes are a subset of leukocytes.

4. **Option D: Hemophilia and Blood Cancer**
- Hemophilia is a genetic disorder that impairs the body's ability to make blood clots.
- Blood cancer refers to various types of cancers that affect the blood, bone marrow, and lymphatic system, such as leukemia.
- **Conclusion:** Hemophilia and blood cancer are entirely different conditions. This pair does not mean the same thing.

### Final Conclusion:
The only pair that means one and the same thing is **Option B: SA Node and Pacemaker**.