Ethyl alcohol fermetation occurs in

Options

A. Lactobacillus
B. muscles of humans
C. Rhizopus
D. all of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Fermentation**: Fermentation is a metabolic process that occurs in the absence of oxygen (anaerobic conditions). It allows organisms to convert sugars into acids, gases, or alcohol.

2. **Types of Fermentation**: There are two main types of fermentation:
- **Lactic Acid Fermentation**: This occurs in certain bacteria (like Lactobacillus) and in human muscle cells when oxygen is scarce. The end product is lactic acid.
- **Ethyl Alcohol Fermentation**: This type occurs in yeast and some fungi, where glucose is converted into ethyl alcohol (ethanol) and carbon dioxide.

3. **Identifying the Organisms**:
- **Lactobacillus**: This bacterium is involved in lactic acid fermentation.
- **Muscles of Humans**: Human muscles also undergo lactic acid fermentation when oxygen is limited.
- **Rhizopus**: This is a type of fungus that can perform ethyl alcohol fermentation.

4. **Analyzing the Options**:
- **Lactobacillus**: Produces lactic acid, not ethyl alcohol.
- **Muscles of Humans**: Also produce lactic acid, not ethyl alcohol.
- **Rhizopus**: Known for producing ethyl alcohol through fermentation.
- **All of These**: This option suggests that all the mentioned organisms can produce ethyl alcohol, which is incorrect.

5. **Conclusion**: The correct answer to the question "Ethyl alcohol fermentation occurs in" is **Rhizopus**, as it is the only organism listed that produces ethyl alcohol through fermentation.

**Final Answer**: Ethyl alcohol fermentation occurs in **Rhizopus**.

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