Permafrost characterizes the biome called

Tundra Biome

Explanation:

Permafrost is a type of soil that is frozen all year round. It consists of rocks, soils and ice. The ice or frost holds the earth materials together.

The tundra biome lies below the arctic circle close to the north pole. Most of the earth here is predominantly frozen all year round. A layer of glacier covers  the surface and a deep lying layer of permafrost follows suit.

Some mountain tops capped with ice shows this tundra features.

Most tundras are termed cold deserts as they have little to no precipitation all year round. There is absence of vegetation cover as a result of low growing season of the plants.  

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)