[2026] PTE Academic Reading - Multiple Choice, Multiple Answers

Tundra ecosystems are among the coldest and harshest biomes on Earth, characterized by low temperatures, minimal precipitation, and a short growing season.A defining feature of the tundra is permafrost, a layer of soil that remains permanently frozen throughout the year.This frozen ground prevents the deep root systems of large trees from taking hold, resulting in a landscape dominated by low-growing plants like mosses, lichens, and small shrubs.The lack of vertical structure and the treeless expanse make the tundra particularly vulnerable to wind erosion and extreme temperature fluctuations.During the brief summer, the surface layer of the permafrost thaws slightly, creating numerous bogs and ponds that become breeding grounds for migratory birds.Animals that inhabit the tundra year-round, such as the arctic fox and snowy owl, have evolved specialized adaptations, including thick fur and camouflage, to survive the sub-zero temperatures.However, the tundra is currently one of the biomes most affected by global climate change.As average temperatures rise, the permafrost is beginning to thaw at an accelerated rate, releasing trapped methane and carbon dioxide into the atmosphere.This process creates a positive feedback loop that further accelerates global warming.Furthermore, the encroachment of boreal forests into warming tundra regions is altering the delicate balance of the existing ecosystem and threatening native species.