Derivative (finance) In finance, a derivative is a contract that derives its value from the performance of an underlying entity. This underlying entity can be an asset, index, or interest rate, and is often simply called the underlying.
Examples. Preservatives are either natural or chemical. Examples of chemical preservatives include nitrates, sulfites, sodium benzoate, potassium sorbate, and propyl gallate. Common natural preservatives include salt, lemon juice (citric acid), vinegar (acetic acid), sugar, and certain spices.unction. Preservatives work in one of three ways. They can prevent growth of microorganisms by creating an environment hostile to them. They can block the process of oxidation that causes foods to turn rancid.
The objective of a wood preservative is to contaminate or change the form of the fourth condition necessary for fungal growth, the food source. By impregnating the wood with a toxic substance, the fungi are unable to utilize the wood for food.