Adding salt and sugar to food substances help in preserving them for a longer durations. It is because excess salt and water

Options

A. Cause rupturing of microbial cells
B. Cause change in the shape of microbial cells
C. Remove water from food
D. Plasmolyse the microbial cells

Explanation

### Step-by-Step Solution:

1. **Understanding Preservation**: The question states that adding salt and sugar helps in preserving food for longer durations. This is due to their ability to affect the water content in food.

2. **Role of Salt and Sugar**: When salt or sugar is added to food, they create a high concentration of solutes outside the microbial cells. This leads to a difference in concentration between the inside of the cell and the surrounding environment.

3. **Osmosis Process**: Water moves from an area of lower solute concentration (inside the microbial cells) to an area of higher solute concentration (outside the cells) through a process called osmosis.

4. **Effect on Microbial Cells**: As water leaves the microbial cells, they undergo a process called plasmolysis, where the cell shrinks due to the loss of water. This partial dehydration of the cells inhibits their growth and reproduction.

5. **Conclusion**: Therefore, the correct answer is that adding salt and sugar causes plasmolysis of microbial cells, which helps in preserving food for longer durations.

### Final Answer:
Adding salt and sugar to food substances helps in preserving them for longer durations because they plasmolyse the microbial cells.

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