"Part and parcel of" is an expression used to describe something that is essential or unavoidable. There are several synonyms that can be used in its place, including "inherent," "integral," "vital," "necessary," and "inseparable." "Inherent" emphasizes the fact that something is a natural part of something else, while "integral" underscores the importance of the item to the overall system. "Vital" indicates that something is essential to the functioning of a particular entity, while "inseparable" stresses the fact that two things cannot be separated from each other without losing their essential characteristics. These synonyms can be used interchangeably to describe something that is crucial and indispensable.