Assertion:Mitochondria are believed to originate by growth and division of previously existing ones .
Reason:They contain DNA and Ribosomes

Options

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

Answer

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

### Step 1: Analyze the Assertion
**Assertion:** Mitochondria are believed to originate by growth and division of previously existing ones.

- This statement is true. Mitochondria replicate through a process similar to binary fission, which is the method used by prokaryotic cells. This supports the idea that they originated from pre-existing mitochondria, aligning with the endosymbiotic theory.

### Step 2: Analyze the Reason
**Reason:** They contain DNA and Ribosomes.

- This statement is also true. Mitochondria have their own circular DNA, similar to that of prokaryotes, and they possess 70S ribosomes, which are characteristic of prokaryotic cells. This further supports the endosymbiotic theory, as it suggests that mitochondria were once independent prokaryotic organisms.

### Step 3: Determine the Relationship
Now, we need to determine if the reason correctly explains the assertion.

- While both the assertion and the reason are true, the reason does not directly explain why mitochondria are believed to originate from pre-existing ones. The presence of DNA and ribosomes supports the idea of their prokaryotic origins but does not explain the mechanism of their growth and division.

### Conclusion
- **Assertion:** True
- **Reason:** True
- **Correct Explanation:** No

Thus, the correct answer is that both the assertion and reason are true, but the reason does not provide a correct explanation for the assertion.

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