AP BIOLOGY

Detailed explanation-1: -One characteristic feature of tundra is that only the surface thaws in the summer and refreezes in the winter, leaving a layer of permanently frozen subsoil. This characteristic is known as . permafrost.

Detailed explanation-2: -One unique characteristic of the Arctic tundra is permafrost–ground that is permanently frozen. Because the permafrost has no cracks or pores, nothing can penetrate it–neither plant roots nor water. The surface layer above the permafrost thaws each summer.

Detailed explanation-3: -Tundra biome is located in the far north and is characterized by persistent soil ice (permafrost) throughout the growing season which in turn does not allow growth of any vegetation.

Detailed explanation-4: -Tundra winters are long, dark, and cold, with mean temperatures below 0°C for six to 10 months of the year. The temperatures are so cold that there is a layer of permanently frozen ground below the surface, called permafrost. This permafrost is a defining characteristic of the tundra biome.

Detailed explanation-5: -Permafrost is a permanently frozen layer on or under Earth’s surface. It consists of soil, gravel, and sand, usually bound together by ice. Permafrost usually remains at or below 0°C (32ºF) for at least two years.