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.
At least 7 billion people
Answer:
rising global temperature which is called the
"Global Warming"
Overcrowding and slums developed in many impoverished countries in the 20th century, mostly due to large migrations to cities from people looking for work.
Cylindrical map projections , conic map projections , & azimuthal map projections.
