Explanation:

- Magnesium Silicate:

- Used mainly as an absorbent and anti-caking agent in food and cosmetics.

- Not a preservative.

- Sodium Palmitate:

- This is a salt of palmitic acid, commonly found in soap.

- It does not act as a preservative.

- Dipropylene Glycol:

- Mainly used as a solvent in cosmetics and industrial applications.

- Not typically used as a preservative.

- Sodium Chloride:

- Also known as common salt.

- It acts as a preservative by inhibiting the growth of bacteria and molds in food.

- Used since ancient times for food preservation.