Answer:
d. Tundra
Explanation:
Tundra is a sort of biome in physical geography, where cold temperatures and short growing seasons hinder the growth of the plant.
This consists of dwarf shrubs, sedges and grasses, mosses and lichens. In some tundra areas, scattered trees are growing.
The tundra-forest ecotone (or ecological boundary region) is called the tree line or timberline.