Assertion. The first codon discovered by Nirenberg and Matthaei was UUU.
Reason. Genetic code translates the language of protein into that of RNA.

Options

A. If both Assertion and Reason are true and the Reason is a correct explanation of the Assertion .
B. If both Assertion and Reason are true but Reason is not a correct explanations of the Assertion
C. If Assertion is true but the Reason is false .
D. If both Assertion and Reason are false.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that "The first codon discovered by Nirenberg and Matthaei was UUU." This is true. In 1961, scientists Marshall Nirenberg and J. Heinrich Matthaei conducted experiments that led to the discovery of the first codon, which was indeed UUU. This codon codes for the amino acid phenylalanine.

2. **Understanding the Reason**: The reason provided states that "Genetic code translates the language of protein into that of RNA." This statement is incorrect. The genetic code actually translates the information from RNA to synthesize proteins, not the other way around. The flow of information follows the central dogma of molecular biology: DNA → RNA → Protein.

3. **Conclusion**: Since the assertion is true and the reason is false, the correct answer to the question is that the assertion is true, but the reason is false.

### Final Answer:
The assertion is true, and the reason is false.

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