I would say A. because it’s the only one that clarifies of what a locomotive really is.
Short term:
•Unification of Mongolia.
•Immediate decline of Jin Dynasty in •China as well as several Central Asian nations including the Kwarezmid Empire.
•Establishment of the Mongol Empire.
•Unification of much of Central Asia, •Northern China, and Mongolia.
•Significant number of deaths (in the millions) resulting from wars and Mongol tactics.
Long Term:
•Increased trade between East and West as the Silk Road was united under one empire.
•Increased cultural exchange between east and west.
•Possibility of the accelerated spread of the Black Death due to the interconnectedness of East and West during the Mongol empire.
•Collapse of the Song Dynasty under Kublai Khan.
•Several descendent states and families from Ghengis Khan which continued to influence course of history in the West, Central, and Southern Asia including the Crimean Khanate, the Golden Horde among others.
•Rise of the prominence of Moscow.
The air pollution is caused by toxic gases such as carbon monoxide
