Question: What basin does the lake that the Argen river flows into belong to?
Sentence (from "Lake Constance"): Lake Constance (German: Bodensee) is a lake on the Rhine at the northern foot of the Alps, and consists of three bodies of water: the "Obersee" or "Upper Lake Constance", the "Untersee" or "Lower Lake Constance", and a connecting stretch of the Rhine, called the "Seerhein".
Relevant evidence: Yes