_________ is a food-preserving method in which water content of food is reduced to prevent microbial growth.

Explanation

The answer to the question is **drying**.

### Step-by-Step Solution:

1. **Understanding Food Preservation**: Food preservation is important to prevent spoilage and maintain the quality of food for a longer time. One of the main causes of food spoilage is microbial growth.

2. **Role of Water in Microbial Growth**: Microorganisms, such as bacteria and fungi, require moisture to grow. When food has a high water content, it becomes susceptible to these microorganisms, leading to spoilage.

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