What defines a swamp?

A swamp is characterized by flat land that has poorly drained conditions, leading to the accumulation of water for prolonged periods. This environment typically supports the growth of various aquatic plants, including trees and shrubs, distinguishing it from other wetland types like marshes, which are dominated by herbaceous plants. The presence of standing water and saturated soils ensures that these ecosystems have unique biodiversity and play crucial roles in filtering water, providing habitat, and mitigating floods.

The other options describe environments that do not fit the definition of a swamp. High elevation with dry soil suggests an environment that lacks the water saturation essential to swamps. Presence of aquatic grasses only excludes the variety of plant life, including trees, that is typically found in swamps. Meanwhile, sandy soil with limited vegetation would indicate a dry, well-drained area rather than the wet conditions that define swamps. Thus, the correct understanding of a swamp as flat land with poorly drained conditions encapsulates the essential features of this type of wetland habitat.