Final answer:
The Yako of Nigeria practicing inheritance from both the father's patrilineal group and the mother's matrilineal group represent ambilineal descent, where families choose kinship lines based on the benefits each side offers.
Step-by-step explanation:
In the case of the Yako of Nigeria, an individual inheriting grazing lands from his father's patrilineal group, and livestock and ritual knowledge from his mother's matrilineal group is an example of ambilineal descent. Ambilineal descent allows each family to choose either the mother's or the father's descent line for their kinship tracing, opting for different opportunities presented by either side. This stands in contrast to unilateral descent systems where lineage is traced exclusively through either the mother's or father's line.