Final answer:
In sociological perspective, two persons on a date form a dyad, which is a two-member group where the existence of the group depends on both individuals being present.
Step-by-step explanation:
In sociological perspective, two persons on a date form a dyad. A dyad is a two-member group, where the existence of the group depends on both individuals being present. If one person withdraws, the dyad can no longer exist. This is similar to a married couple or two best friends who stop talking. In contrast, a triad is a three-member group where the dynamic is different. If one person withdraws, the group can still continue to exist.