Probes used in DNA finger printing are :

Options

A. highly sensitive electron microscope
B. UV beams
C. X-ray scanners
D. DNA segments having radioactive isotopes

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the types of probes used in DNA fingerprinting. Probes are essential tools in molecular biology that help identify specific sequences of DNA.

2. **Identifying the Options**: The options provided are:
- A) Highly sensitive electron microscope
- B) UV beams
- C) X-ray scanners
- D) DNA segments having radioactive isotopes

3. **Analyzing Each Option**:
- **Option A: Highly sensitive electron microscope**: This is an imaging tool used to visualize small structures at a molecular level but is not a probe used in DNA fingerprinting.
- **Option B: UV beams**: While UV light can be used in various applications in molecular biology, it is not a probe for DNA fingerprinting.
- **Option C: X-ray scanners**: Similar to the previous options, X-ray scanners are not used as probes in DNA fingerprinting.
- **Option D: DNA segments having radioactive isotopes**: This is the correct choice. Radioactively labeled DNA probes are specifically designed to bind to complementary DNA sequences and are used to detect the presence of specific nucleotide sequences in DNA samples.

4. **Conclusion**: The correct answer to the question is option D, which refers to DNA segments having radioactive isotopes.

**Final Answer**: The probes used in DNA fingerprinting are DNA segments having radioactive isotopes.

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