What is correct regarding leucocytes?

Options

A. These can squeeze out through the capillary walls
B. These are enucleate
C. Sudden fall in their number indicates cancer
D. These are produced in thymus

Answer

### Step-by-Step Solution:

1. **Understanding Leucocytes**: Leucocytes, or white blood cells, are a crucial part of the immune system, helping the body to fight infections and other diseases.

2. **Analyzing the Statements**:
- **Statement 1**: "These can squeeze out through the capillary walls."
- This statement is correct. Leucocytes can indeed move out of the bloodstream and into tissues, a process known as diapedesis.

- **Statement 2**: "These are enucleated."
- This statement is incorrect. Leucocytes are not enucleated; they contain a nucleus. In fact, they are distinct from red blood cells, which are enucleated.

- **Statement 3**: "Certain fall in the number indicates cancer."
- This statement is also incorrect. A decrease in white blood cell count is referred to as leukopenia, which can indicate various conditions, but not specifically cancer.

- **Statement 4**: "These are produced in thymus."
- This statement is incorrect as well. While T cells mature in the thymus, leucocytes (white blood cells) are primarily produced in the bone marrow.

3. **Conclusion**: The only correct statement regarding leucocytes is that they can squeeze out through capillary walls (Statement 1). The other statements are incorrect.

### Final Answer:
The correct statement regarding leucocytes is: "These can squeeze out through the capillary walls."

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