Describe the Hudson Bay-Arctic Lowlands and Arctic region and their typical ecosystems.

• A. The lowlands are flat, waterlogged plains with muskeg and permafrost in the north; ecosystems range from boreal forests in the south to tundra and polar deserts in the north.
• B. The lowlands are high plateaus with deserts; ecosystems are alpine and tropical.
• C. The lowlands are rolling hills with rich soils; ecosystems are deciduous forests and grasslands.
• D. The lowlands are coastal marshes with mangroves; ecosystems are tropical rainforest.

Answer: (A)

The main idea is how the landscape and climate of the Hudson Bay–Arctic region shape the living communities from south to north. These lowlands are typically flat and very waterlogged, with extensive muskeg (peat-forming bogs) and soils underlain by permafrost in the northern parts. That permafrost keeps the ground cold and soggy, so drainage is poor and wetlands dominate. As you move south, the climate becomes milder enough to support boreal forests, so coniferous trees and related taiga ecosystems appear. Moving farther north, the cold, short growing seasons and permafrost limit tree growth, giving way to tundra—a treeless, shrub-and-m moss-and-lichen-dominated ecosystem. At the far northern edge, conditions are so harsh and precipitation so low that only sparse vegetation remains, which is characteristic of a polar desert. This combination of flat, waterlogged lowlands with a gradual ecological shift from boreal forests to tundra and finally to polar deserts explains the description of the Hudson Bay–Arctic Lowlands and Arctic region.