Answer:
A
Explanation:
Subsequent boundaries are boundaries that were there before a place was established.
Example: Berlin and the wall of Berlin.
Hope this helps :)
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.
It's gets colder, wetter, and not much sun is received.
The answer to your question would be d.aquifer Hope this helps:)
