The United States stopped Southern Korea from becoming a Communist nation.
The Brezhev Doctrine asserted that the Soviet Union would interfere in Eastern European nations to preserve the communist rule. It also would seek a disarmament agreement with NATO.
Air pollution
Highway congestion
Air pollution has caused it because the engine of the cars has made the smell of the air be not very nice, and people could end up being ill because of having to breathe in petrol, because they might have an allergen.
Highway congestion because there are so many cars these days, that most of the time you go on a highway (motorway), there are loads of cars queueing. This can also cause air pollution because the animals that might be in a field at the side of the motorway won't like the smell of all those cars.
The answer is #4, but depending on where they lived and which Europeans had conquered them.
Protestant English, Dutch, Swedes viewed Natives as subhuman and therefore on fit for extermination no matter what the Natives did or acted.
The Catholic Spanish viewed Natives as humans with certain rights, and a source of cheap labor. Therefore in order to use the Natives to their advantage, the Natives had to be alive and live somewhere.
