Answer:
mountain ridges creating natural divides
Explanation:
Natural boundaries acting as controls for water flow and makes them move into oceans are typically mountain ridges. They are geographically called divides.
Water generally flows from regions of high elevations to flat lands and plains.
Oceans the final basin where water from lands flows into. Ocean basins are located at very low elevation and through this potential head, gravity allows all land water to flow ocean-ward.
Mountains are sources of inland water bodies and they control how these rivers flows. Therefore, they act as natural divides that guides rivers into basins.
