The following paragraphs are from a natural science passage discussing beaver dams:
[Paragraph 1]
Beavers are well-known for building wooden dams across streams and small rivers. By piling branches, logs, stones, and mud, they block the natural flow of water, which forces it to pool upstream. This construction process transforms a quick-moving stream into a deep, quiet pond that serves as a safe home for the beaver family.
[Paragraph 2]
In addition to providing shelter, these beaver ponds act as natural filtration systems. As the blocked water slows down, suspended dirt, sand, and organic debris sink to the bottom of the pond rather than floating downstream. This trapping of sediment helps clean the water, reducing the accumulation of silt in larger reservoirs and lakes further down the river system.
[Paragraph 3]
Furthermore, the quiet water and surrounding wetlands created by the dams attract many other species. Algae and aquatic plants thrive in the still ponds, providing food for insects, fish, and amphibians. In turn, these creatures draw waterfowl, birds of prey, and mammals, making beaver ponds hotspots of biological diversity.
Match each paragraph from the passage to its primary paragraph-level main idea.
- Paragraph 1The physical alteration of waterways by beavers to establish a home environment
- Paragraph 2The capacity of beaver ponds to trap sediments and improve water clarity
- Paragraph 3The creation of diverse wetland habitats that promote biodiversity