Which type of descent refers to groups that only trace lineage through either the mother or father?

The correct answer is unilineal descent, which specifically refers to the tracing of lineage through one gender only, either the mother or the father. This concept is essential in understanding how different societies organize kinship and inheritance.

In unilineal descent, if the lineage is traced through the mother, it is known as matrilineal descent, while if it is traced through the father, it is known as patrilineal descent. This system creates distinct family groups and can have implications for property rights, social roles, and affiliation within communities. By focusing exclusively on one line of descent, societies that practice unilineal descent simplify their social structure and designate clear inheritance patterns.

Cognatic descent, as a contrasting concept, allows for the tracing of lineage through both maternal and paternal lines, leading to a more complex kinship structure. Similarly, bilaterally descended refers to the practice of recognizing both sides of the family equally without favoring one lineage, which does not align with the definition of unilineal descent. Therefore, unilineal descent accurately captures the idea of tracing lineage through only one parent, distinguishing it clearly from other kinship systems.