Yeast is used in preparation of

Options

A. acetic acid
B. curd
C. ethyl alcohol
D. cheese

Answer

**Step-by-Step Solution:**

1. **Identify the Organism**: Recognize that yeast is a type of fungus, specifically the species Saccharomyces cerevisiae, which is commonly used in various fermentation processes.

2. **Understand the Role of Yeast**: Yeast is primarily known for its ability to convert carbohydrates (sugars) into alcohol and carbon dioxide through the process of fermentation.

3. **Evaluate the Options**:
- **Acetic Acid**: This is produced by acetic acid bacteria, not yeast. Therefore, this option is incorrect.
- **Curd**: The fermentation of milk into curd is primarily done by bacteria such as Lactobacillus, not yeast. This option is also incorrect.
- **Ethyl Alcohol**: Yeast, particularly Saccharomyces cerevisiae, is responsible for the fermentation process that produces ethyl alcohol. This option is correct.
- **Cheese**: The production of cheese involves bacteria like Lactobacillus and Streptococcus, not yeast. Thus, this option is incorrect.

4. **Conclusion**: Based on the evaluation of the options, the correct answer is that yeast is used in the preparation of ethyl alcohol.

**Final Answer**: Yeast is used in the preparation of ethyl alcohol.

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