Question

how do wetlands form?
○ tributaries flow into rivers.
○ runoff travels down the side of a divide.
○ water builds up in a depression left by an ice sheet.
○ groundwater comes to the surface and floods the land.

Explanation:

Wetlands form when water accumulates on land, creating saturated conditions. Let's analyze each option:

1. Tributaries flowing into rivers creates larger rivers, not wetlands.
2. Runoff down a divide is part of surface water flow to rivers, not wetland formation.
3. While glacial depressions can form wetlands (like potholes), it is not the only or most general way.
4. Groundwater rising to the surface and flooding land directly creates the saturated, waterlogged conditions that define wetlands, and this is a common and broad mechanism for wetland formation.

Answer:

D. Groundwater comes to the surface and floods the land.