The most unstable molecule is

Options

A. ss DNA
B. ds RNA
C. m RNA
D. t RNA

Answer

To determine the most unstable molecule among the given options, we need to analyze each one based on its structure and stability.

### Step-by-Step Solution:

1. **Identify the Options**: The options provided are:
- Single-stranded DNA
- Double-stranded RNA
- mRNA
- tRNA

2. **Evaluate DNA Stability**:
- DNA is typically more stable due to its double-helix structure and the presence of deoxyribose sugar. It is less prone to degradation compared to RNA.
- **Conclusion**: Single-stranded DNA is not the answer.

3. **Evaluate Double-Stranded RNA**:
- Double-stranded RNA (dsRNA) has a stable structure due to complementary base pairing, similar to double-stranded DNA.
- **Conclusion**: Double-stranded RNA is not the answer.

4. **Evaluate mRNA**:
- mRNA (messenger RNA) is synthesized from DNA and is known to be relatively unstable. It undergoes various modifications and is quickly degraded after translation.
- **Conclusion**: mRNA is likely to be the most unstable molecule among the options.

5. **Evaluate tRNA**:
- tRNA (transfer RNA) is also relatively stable as it plays a crucial role in translation by carrying amino acids to the ribosome. It has a cloverleaf structure that contributes to its stability.
- **Conclusion**: tRNA is not the answer.

6. **Final Conclusion**:
- After evaluating all options, mRNA is identified as the most unstable molecule due to its transient nature and quick degradation after its role in protein synthesis.

### Answer:
The most unstable molecule is **mRNA**.

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