A river and all of its tributaries form what?

• A. River system
• B. Watershed
• C. Wetlands
• D. Ponds and lakes

Answer: (A)

A river system is the network formed by a river and all of its tributaries. Each tributary is a branch that feeds into the main river, together creating a connected system that transports water toward a common outlet. The surrounding land area that collects and channels this water is called the watershed, which is related but separate from the network of rivers and streams itself. Wetlands, ponds, and lakes are separate features and do not describe this flowing channel network.