For testing Oparin's hypothesis Stanley Miller and Harold Urey used `H_2,NH_3` and two other chemicals which were

Options

A. `O_2` and methane
B. `O_2" and "H_2O`
C. `CH_4" and "H_2O`
D. Salt and `H_2O`

Answer

To answer the question regarding the chemicals used by Stanley Miller and Harold Urey in their experiment to test Oparin's hypothesis, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Oparin's Hypothesis**: Oparin's hypothesis suggests that life originated from simple inorganic compounds that formed more complex organic molecules under the conditions of the early Earth.

2. **Identifying the Experiment**: Stanley Miller and Harold Urey conducted an experiment to simulate the conditions of the primitive Earth atmosphere to test this hypothesis.

3. **Recognizing the Chemicals Used**: In their experiment, they used a mixture of gases that were believed to be present in the early atmosphere. The gases included:
- Hydrogen (H₂)
- Ammonia (NH₃)
- Methane (CH₄)
- Water vapor (H₂O)

4. **Eliminating Incorrect Options**:
- **Oxygen and Methane**: Incorrect because the early atmosphere was thought to be reducing, not oxidizing.
- **Oxygen and Water**: Incorrect for the same reason as above; oxygen was not present in significant amounts.
- **Salt and Water**: Incorrect as salt is not one of the gases used in the experiment.

5. **Conclusion**: The correct answer is that Miller and Urey used hydrogen, ammonia, methane, and water vapor in their experiment.

### Final Answer:
The two other chemicals used by Stanley Miller and Harold Urey, along with hydrogen and ammonia, were methane (CH₄) and water vapor (H₂O).

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