A Both have polution problems and B both have effective mass transit systems also D both are culturally important to their respective countries.
Check A,B,D
Answer:
volcano
A volcano is most commonly a conical hill or mountain built around a vent that connects with reservoirs of molten rock below the surface of the Earth. The term volcano also refers to the opening or vent through which the molten rock and associated gases are expelled.
Explanation:
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Answer: Mongolia declared its independence from the Soviet Union.