________ is used to preserve food items such as jams, jellies and squashes.

Options

A. Sugar
B. Salt
C. Ultra-heat Treatment
D. Oil

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a substance used to preserve food items like jams, jellies, and squashes.

2. **Identifying Preservation Methods**: Food preservation methods include various techniques such as refrigeration, canning, and the use of preservatives. In this case, we focus on a specific method related to jams, jellies, and squashes.

3. **Recognizing the Role of Sugar**: Sugar plays a crucial role in preserving these food items. It acts as a preservative by creating a hypertonic environment.

4. **Explaining Hypertonic Solution**: When a high amount of sugar is added to jams, jellies, and squashes, it creates a hypertonic solution. This means that the concentration of solutes (sugar) outside the microbial cells is higher than inside.

5. **Understanding Osmosis**: Due to osmosis, water moves from an area of low solute concentration (inside the microbial cells) to an area of high solute concentration (the sugary medium).

6. **Effect on Microbial Cells**: As water exits the microbial cells, they lose water and shrink. If they lose too much water, they cannot survive, leading to the death of these microbes.

7. **Conclusion**: Therefore, the substance used to preserve food items such as jams, jellies, and squashes is **sugar**.

**Final Answer**: Sugar is used to preserve food items such as jams, jellies, and squashes.

---