Final answer:
Ambilineal descent is a kinship system that allows families to trace their lineage through either the mother's or the father's side, whereas bilateral descent traces kinship through both parents' lines.
Step-by-step explanation:
The term ambilineal refers to a type of unilateral descent system in which an individual's kinship is traced through either the mother's or the father's lineage, depending on the choice made by each family. Unlike patrilineal descent, which follows the father's line exclusively, or matrilineal descent, which follows the mother's side exclusively, ambilineal descent allows for flexibility and can shift based on considerations such as social prestige or economic opportunities. In these societies, the choice of descent might be made at the time of marriage, and it is then applied consistently to all children within the family. The decision can be influenced by multiple factors, from the desire to align with more prestigious kinship lines to various cultural customs. In contrast, bilateral descent traces an individual's kinship through both parents' lines and is the most common form of descent found in societies like the United States.