Assertion :- Operon concept is applicable only in prokaryotes.
Reason : Gene expression in prokaryotes is influenced by environmental conditions.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are trur but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is Flase.
D. If both Assertion & Reason are false.

Answer

To solve the assertion and reason question, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
The assertion states: "Operon concept is applicable only in prokaryotes."

- The operon concept was first described by Jacob and Monod through their studies on the lac operon in *Escherichia coli* (E. coli).
- An operon is a cluster of genes under the control of a single promoter and is primarily found in prokaryotes.
- This concept explains how genes can be regulated together in response to environmental changes, particularly in bacteria.

**Conclusion for Step 1:** The assertion is true because the operon concept is indeed applicable only to prokaryotes.

### Step 2: Analyze the Reason
The reason states: "Gene expression in prokaryotes is influenced by environmental conditions."

- It is true that gene expression in prokaryotes can be influenced by environmental conditions, such as the presence of specific nutrients or stress factors.
- However, this statement is too broad and does not specifically address the mechanisms of gene regulation in prokaryotes, such as transcriptional control, which is the primary method of regulation.
- While environmental factors do influence gene expression, the statement does not accurately reflect the primary mechanism of gene regulation in prokaryotes.

**Conclusion for Step 2:** The reason is incorrect because it does not adequately explain the specific mechanisms of gene expression regulation in prokaryotes.

### Final Conclusion
- The assertion is true, while the reason is false. Therefore, the correct answer is that only the assertion is true.

### Summary of the Answer
- Assertion: True
- Reason: False
- Correct choice: Only the assertion is true.

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