Here are some key characteristics of a tundra:

* Low temperatures: The average annual temperature is below freezing, with very cold winters and short, cool summers.

* Low precipitation: Tundra ecosystems receive very little precipitation, usually less than 10 inches per year.

* Permafrost: The ground is permanently frozen, except for a shallow layer that thaws during the short summer months.

* Limited vegetation: Due to the harsh conditions, tundra ecosystems have a limited variety of plant life, primarily consisting of low-lying shrubs, grasses, mosses, and lichens.

* Unique wildlife: Animals that live in the tundra have adapted to the cold and harsh conditions, including caribou, arctic foxes, lemmings, and snowy owls.

There are two main types of tundra:

* Arctic tundra: Located in the northern hemisphere, surrounding the Arctic Ocean.

* Alpine tundra: Found at high altitudes in mountain ranges around the world.