Assertion : The first living organisms on earth were autotrophs.
Reason : They were capable of performing chemosynthesis.

Options

A. A.If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion, then mark (1)
B. B.If both Assertion and Reason are true ,but the Reason is not the correct explanation of the Assertion, then mark (2).
C. C.If Assertion is true, but Reason is false , then mark (3)
D. D.If both Assertion and Reason are false. , then mark (4)

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that the first living organisms on Earth were autotrophs. Autotrophs are organisms that can produce their own food from inorganic substances, typically through processes like photosynthesis or chemosynthesis.

2. **Evaluating the Assertion**: This assertion is false. The first living organisms on Earth were not autotrophs; they were likely chemoheterotrophs. Chemoheterotrophs are organisms that obtain their energy and carbon by consuming organic compounds, rather than producing their own food.

3. **Understanding the Reason**: The reason provided states that these first organisms were capable of performing chemosynthesis. Chemosynthesis is a process used by some autotrophs to convert inorganic compounds into organic matter using chemical energy, rather than sunlight.

4. **Evaluating the Reason**: This reason is also false. The first living organisms were not autotrophs and therefore did not perform chemosynthesis. Instead, they absorbed organic materials from their environment for nourishment.

5. **Conclusion**: Since both the assertion and the reason are false, the correct answer is that both the assertion and the reason are false.

**Final Answer**: Both assertion and reason are false.

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