Final answer:
Low shrubs (option 3) are the predominant plant in Canada's cold Arctic Archipelago, adapted to grow in the shallow soil during the Arctic summer.
Step-by-step explanation:
Low shrubs are predominant plants in Canada's cold Arctic Archipelago (option 3). In the Arctic tundra, the presence of frost that is permanent restricts the depth at which a plant's roots can grow, resulting in plant life that is generally low to the ground. This includes low shrubs, grasses, low-growing plants like shrub willow, and small flowering plants. These plants are adapted to withstand the harsh, cold environment with little species diversity, low net primary productivity, and low above-ground biomass.
Tall trees cannot survive in such conditions due to the short growing season, while grasses, though present, are not the predominant vegetation.