The bread or idli dough rises because of:

Options

A. heat
B. grinding
C. growth of yeast cells
D. kneading

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks why bread or idli dough rises. This is a common phenomenon in baking and cooking, and it is essential to identify the biological process behind it.

2. **Identifying the Key Organism**: The primary organism responsible for the rising of the dough is yeast. Yeast is a type of fungus that plays a crucial role in fermentation.

3. **Role of Yeast in Dough Rising**: When yeast is added to the dough, it begins to grow and multiply. This growth is a vital part of the process that leads to the dough rising.

4. **Respiration Process**: As yeast cells grow, they undergo a process called respiration. During respiration, yeast consumes sugars and produces carbon dioxide (CO2) and alcohol.

5. **Effect of Carbon Dioxide**: The carbon dioxide gas produced during yeast respiration gets trapped in the dough, causing it to expand and rise. This is what makes the bread or idli dough fluffy and light.

6. **Conclusion**: Therefore, the correct answer to the question is that the bread or idli dough rises because of the growth of yeast cells, which produce carbon dioxide during respiration.

**Final Answer**: The bread or idli dough rises because of the growth of yeast cells, which produce carbon dioxide during respiration.

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