Fruits and jams are preserved by ________

Options

A. smoking
B. heating
C. oiling
D. adding sugar

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how fruits and jams are preserved. This involves identifying the method or substance used to prevent spoilage.

2. **Analyzing the Options**: The options given are:
- Smoking
- Heating
- Oiling
- Adding sugar

3. **Identifying the Correct Method**:
- **Smoking**: This method is typically used for preserving meats and fish, not fruits or jams.
- **Heating**: While heating can be used in canning processes, it is not the primary method for preserving fruits and jams in the context of this question.
- **Oiling**: This method is not commonly associated with preserving fruits or jams.
- **Adding Sugar**: This is a well-known method for preserving fruits and jams. Sugar helps to inhibit the growth of microorganisms that cause spoilage.

4. **Conclusion**: Based on the analysis, the correct answer is that fruits and jams are preserved by **adding sugar**. Sugar not only acts as a preservative but also enhances the flavor of the jams.

**Final Answer**: Fruits and jams are preserved by **adding sugar**.

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