History was a driving force behind such migration, since humans tended to move to new territory when they lacked food, shelter, or other resources--meaning that most of the conflicts throughout history have been driven by the same forces that drove migration out of Africa.
That would be B. Latin America
The state of being scarce or in short supply; shortage.
Basically being low on a resource (lacking it)
An example would be if you were stuck in a desert, water would be scarce.
Global warming is heating up the planet making icecaps melt and increase the ocean water level versus global cooling makes temperatures drop turning tropical places into snowy weather and yeah.. that’s what I know