A correct pair of characteristics of molecular probe is-
A. Very long molecule
B. Double stranded
C. Single stranded DNA or RNA
D. Complementary to part of desired gene

Options

A. A and B
B. B and C
C. C and D
D. A and D

Answer

To determine the correct pair of characteristics of molecular probes, we need to analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Molecular Probes**:
- Molecular probes are short segments of DNA or RNA that can hybridize (bind) to complementary sequences in nucleic acids. Their primary function is to detect specific sequences within a larger DNA or RNA molecule.

2. **Analyzing Option A (Very long molecule)**:
- Molecular probes are not very long; they are typically short sequences. Therefore, this option is incorrect.

3. **Analyzing Option B (Double stranded)**:
- Molecular probes are usually single-stranded. Double-stranded molecules do not serve the purpose of probing for complementary sequences effectively. Thus, this option is also incorrect.

4. **Analyzing Option C (Single stranded DNA or RNA)**:
- This option is correct. Molecular probes are indeed single-stranded DNA or RNA that can hybridize with complementary sequences.

5. **Analyzing Option D (Complementary to part of desired gene)**:
- This option is also correct. Molecular probes are designed to be complementary to specific sequences in the target DNA or RNA, allowing them to bind effectively.

6. **Conclusion**:
- The correct pair of characteristics for molecular probes is found in options C and D. Therefore, the answer is C (Single stranded DNA or RNA) and D (Complementary to part of desired gene).

### Final Answer:
- The correct characteristics of molecular probes are **C (Single stranded DNA or RNA)** and **D (Complementary to part of desired gene)**.