Passage
Though often viewed by landowners as mere pests due to their habit of felling trees and flooding property, beavers are actually vital ecological engineers whose activities shape entire landscapes. When beavers construct dams across streams, they slow the flow of water, transforming narrow channels into expansive wetlands and ponds. These newly created aquatic habitats serve as critical breeding grounds for countless amphibian species, such as frogs and salamanders, which require still water to lay their eggs. Furthermore, the standing water behind a beaver dam filters suspended sediment from the stream, improving water quality downstream. The saturated soil surrounding these ponds also encourages the growth of lush, moisture-loving vegetation, which in turn attracts diverse insect populations and nesting waterfowl. By modifying their physical environment in this way, beavers establish complex, resilient ecosystems that support a far greater variety of plant and animal life than would exist in a simple flowing stream. Ultimately, the presence of beavers is a primary driver of local biodiversity, illustrating how a single species can fundamentally rebuild and enrich its environment.
Based on the passage, which of the following statements best expresses the main point about beavers?
- AThe standing water created by beaver dams filters sediment to improve downstream water quality.
- Beavers establish complex wetland environments that support and enrich a wide variety of plant and animal life.Answer
- CBeavers are unique because they are the only animals capable of altering physical landscapes.
- DBeaver dams create still-water habitats that are essential for frogs and salamanders to lay their eggs.