The blood cell that is a precursor to microglial, cell is –

Options

A. A basophil
B. A monocyte
C. A neutrophil
D. A lymphocyte

Answer

### Step-by-Step Solution:

1. **Understanding Microglial Cells**: Microglial cells are a type of glial cell located in the central nervous system. They act as the primary immune defense in the brain and spinal cord.

2. **Identifying Precursors**: To determine the precursor of microglial cells, we need to look at the types of blood cells that can differentiate into microglial cells.

3. **Types of Blood Cells**: The main types of white blood cells (leukocytes) include basophils, neutrophils, lymphocytes, and monocytes. Each of these plays a different role in the immune system.

4. **Focusing on Monocytes**: Among these, monocytes are known to differentiate into macrophages, which are involved in immune responses. Macrophages can further differentiate into microglial cells in the central nervous system.

5. **Conclusion**: Therefore, the blood cell that is a precursor to microglial cells is the monocyte.

### Final Answer:
The blood cell that is a precursor to microglial cells is the **monocyte**.

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