Jams are preserved by:

Options

A. salts
B. sugars
C. pasteurisation
D. irradiation

Explanation

**Step-by-Step Solution:**

1. **Understanding the Composition of Jams:**
- Jams are primarily made from fruits and sugar. The sugar not only adds sweetness but also plays a crucial role in preservation.

2. **Analyzing the Preservation Methods:**
- The question provides four options for preserving jams:
- (1) Salt
- (2) Sugar
- (3) Pasteurization
- (4) Irradiation

3. **Evaluating Each Option:**
- **Salt:** While salt is a common preservative, it is typically used for savory foods and can alter the taste of sweet items like jams.
- **Sugar:** Sugar is the primary preservative for jams. It creates a high osmotic pressure that inhibits the growth of microorganisms, making it difficult for them to survive in the jam.
- **Pasteurization:** This method involves heating to kill bacteria and is more commonly used for liquids rather than solid preserves like jams.
- **Irradiation:** This is a method used to kill bacteria and pests in food, but it is not a traditional method for preserving jams.

4. **Conclusion:**
- Based on the analysis, the most effective and appropriate method for preserving jams is **sugar**. Therefore, the correct answer is option (2) Sugar.

**Final Answer:**
Jams are preserved by: **Sugar.**

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