Answer:
The climate region labeled with number 4 is the tundra, characterized by a very cold and dry climate, and low diversity of organisms that are highly specialized.
Step-by-step explanation:
The tundra is a climate region that is found in the northernmost parts of Asia, Europe, and North America. This climate region is characterized by very low temperatures are year-round, and even when it is summer the temperatures are relatively low. The precipitation levels are also very low, and when there are any they come in the form of snow. The winds tend to be very strong and very cold.
The animals and plants that live in the tundra are all highly specialized. The plants tend to be very small, close to the ground, and are able to withstand extremely cold temperatures and a very long period of being inactive. The animals have very thick fur, often double layer, preserve a lot of fat, have wider nostrils, wider paws, and their ears tend to be very small to avoid freezing. Some of the plants that can be found here are the lichens and mosses, while from the animals there are polar bears, Arctic foxes, lemmings, walruses, multiple species of seals...