Who proposed that the first form of life could have come from pre-existing non-living organic molecules ?

Options

A. S.L. Miller
B. Oparin & Haldane
C. Charles Darwin
D. Alfred Wallace

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the scientists who proposed that the first form of life could have originated from pre-existing non-living organic molecules.

2. **Identifying Key Scientists**: The two scientists credited with this idea are Alexander Oparin and J.B.S. Haldane.

3. **Oparin's Contribution**: Alexander Oparin, a Russian biochemist, proposed the theory of chemical evolution. He suggested that life began in a "primordial soup" of organic molecules, which were formed from non-living substances.

4. **Haldane's Support**: J.B.S. Haldane, an English scientist, supported Oparin's theory. He also contributed ideas about the conditions of early Earth that could lead to the formation of organic compounds.

5. **The Primordial Soup Hypothesis**: Both scientists theorized that the early Earth had a reducing atmosphere rich in gases like ammonia, methane, hydrogen, and water vapor. Under the influence of energy sources like lightning, these gases could react to form simple organic molecules.

6. **Conclusion**: Therefore, the correct answer to the question is that the theory was proposed by Alexander Oparin and supported by J.B.S. Haldane.

**Final Answer**: Alexander Oparin and J.B.S. Haldane proposed that the first form of life could have come from pre-existing non-living organic molecules.

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