Scientist believe that life on earth originated by

Options

A. Spontaneous generation
B. Chemical evolution/ abiogenesis
C. Sepcial creation
D. Extra terrestrial transfer

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the scientific beliefs regarding the origin of life on Earth.

2. **Identifying Theories**: There are several theories regarding the origin of life, including:
- **Special Creation**: Proposed by Father Swartz, this theory suggests that God created life in a specific manner over six days, with Earth being around 4000 years old.
- **Catastrophism**: This theory posits that life was shaped by sudden, catastrophic events.
- **Biogenesis**: This theory states that life arises from pre-existing life.
- **Spontaneous Generation**: This outdated theory suggested that life could arise from non-living matter.
- **Cosmic Theory (Cosmozoic Theory)**: This theory suggests that life may have originated from extraterrestrial sources.

3. **The Most Accepted Theory**: Among these theories, the most widely accepted one is the **Theory of Chemical Evolution**, proposed by scientists Alexander Oparin and John Haldane. This theory suggests that life originated from the gradual formation of organic molecules from inorganic compounds.

4. **Supporting Evidence**: The validity of the Theory of Chemical Evolution was supported by the experiments conducted by Stanley Miller and Harold Urey in the 1950s. They demonstrated that organic compounds could be synthesized from inorganic precursors under conditions thought to resemble those of early Earth.

5. **Conclusion**: Based on the evidence and acceptance in the scientific community, the most credible explanation for the origin of life on Earth is the **Theory of Chemical Evolution (or Abiogenesis)**.

**Final Answer**: Scientists believe that life on Earth originated by the Theory of Chemical Evolution or Abiogenesis.

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