Final answer:
A natural waterway where fresh water flows into another area like the ocean is a river. Rivers carry water from their source to a lake or ocean, while estuaries are areas where rivers meet the ocean, mixing fresh and salt water.
Step-by-step explanation:
A natural waterway where fresh water flows from one area to another area such as the ocean is a river. Rivers and streams are continuously moving bodies of water that carry large amounts of water from the source, or headwater, to a lake or ocean. Examples of large rivers include the Nile River in Africa, the Amazon River in South America, and the Mississippi River in North America.
An estuary is where a river meets the ocean, blending fresh water with salt water, creating a unique biome known for its high biodiversity and productivity, such as the San Francisco Bay. Unlike rivers, estuaries have a mix of saline and fresh water and are influenced by the tides, with varying salinity that supports diverse wildlife.