According to Oparin, which one of the following was not present in the primitive atmospehre of the earth?

Options

A. Methane
B. Oxygen
C. Hydrogen
D. Water vapour

Answer

**Step-by-Step Solution:**

1. **Understanding Oparin's Hypothesis**: Oparin proposed a theory about the composition of the primitive atmosphere of Earth. He suggested that the early atmosphere was vastly different from what we have today.

2. **Identifying Components of Primitive Atmosphere**: According to Oparin, the primitive atmosphere consisted mainly of gases such as methane (CH₄), ammonia (NH₃), hydrogen (H₂), and water vapor (H₂O). These gases were essential for the formation of organic compounds.

3. **Absence of Free Oxygen**: One of the key points in Oparin's hypothesis is that there was no free oxygen (O₂) present in the primitive atmosphere. The atmosphere was reducing, meaning it lacked oxygen, which is crucial for combustion and respiration processes.

4. **Conclusion**: Based on Oparin's theory, the gas that was not present in the primitive atmosphere of Earth is oxygen. Therefore, the correct answer to the question is oxygen.

**Final Answer**: Oxygen was not present in the primitive atmosphere of Earth according to Oparin.

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