Final answer:
The Coco river, also known as the Segovia river, is the river that forms part of the border between Nicaragua and Honduras. It is a significant part of Central American geography.
Step-by-step explanation:
The river that forms part of the border between Nicaragua and Honduras is known as the Coco river, also referred to as the Segovia river. This waterway is significant in the context of Central American geography, serving as a natural boundary and belonging to a region with diverse ecosystems.
It is neither the Ganges, the Nile, nor the Danube, as these are famous rivers located in Asia and Europe respectively.