Step 1: Understanding the Concept:
The question asks for the primary function of a refrigerator, a common household appliance.
Step 2: Detailed Explanation:
- Refrigeration: This is the process of making and keeping things (especially food and drinks) cool by storing them in a refrigerator. The low temperature slows down the growth of bacteria and other microorganisms, thus preserving the food for a longer time. The name "refrigerator" itself points to this function.
- Fermentation: This process, used to make things like yogurt or bread, often requires a warm environment to encourage microbial growth, which is the opposite of what a refrigerator does.
- Dehydration: This is the process of removing water or moisture from food, often using heat or air circulation, which is not a function of a standard refrigerator.
Step 3: Final Answer:
A refrigerator is used for refrigeration.