State any four beneficial effects of bacteria.

Explanation

**Step-by-Step Text Solution:**

1. **Nitrogen Fixation in Agriculture**:
Bacteria play a crucial role in agriculture by fixing nitrogen. Certain bacteria, such as *Rhizobium*, convert atmospheric nitrogen into ammonia, which is then utilized by plants for growth. This process enriches the soil and enhances plant productivity.

2. **Production of Acetic Acid**:
Bacteria are used in the fermentation process to produce acetic acid, which is a key ingredient in vinegar. This process is important in the food industry for preserving food and enhancing flavors.

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