After the build up of anxiety from Nationalism, Imperialism and Militarism, the Powers were worried about being attacked by each other.To counter this alliances were formed. Germany made a mystery alliance with Austria-Hungary in 1879. The Alliance System was certainly a prominent reason of WWI.
Tundras and deserts have a number of similarities such as their lack of water or how organisms that inhabit them are have special features to survive their extreme weather. Both are nearly unsustainable for human life and have just like the tundra, deserts have freezing temperatures at night.
