I'm pretty sure it's railroads, because there's not that many highways in Siberia, the rivers would be frozen over, and there's not a ton of people in Siberia. I'm sorry if I'm wrong.
Temperature and density increases from the crust to the core.
Answer: The Precambrian Era comprises all of geologic time prior to 600 million years ago.
Explanation: The Precambrian was originally defined as the era that existed before the emergence of life in the Cambrian Period. It is known that life on Earth began by the early Archean and that fossilized organisms became more and more abundant throughout Precambrian time.
Answer:
In a federal system there is no centralized authority, while in a confederal system power is distributed equally among the states.
Explanation:
The Federal government is a type of government in which sovereign power rests with the central government, while in a confederal government political power rests with individual states and very little with the central government.
Answer:
The heat equation can be written as. ∂ u ∂ t = α ∇ 2 u. where u(x, y, t) is the temperature field that varies in space and time, and α is the thermal diffusivity constant.