* Pollution * Population or * Overcrowding * Use of natural resources * Energy usage or * Toxic waste. * Gaps in global wealth. * Greenhouse gas emissions. * Urbanization.
Population
Pollution
Oceans and deep rivers form natural boundaries because they restrict human and animal migration.
The Amazon River system
During the last ice age.
Areas that had been covered tended to industrialize earlier.
The world got smaller and cultures mixed, and international trade provided increased economic growth.
Some things that have helped make the world more connected are:
The internet
The printing press
Railroads
Ships
Planes
Brazil has a population nearly 20 times larger than Portugul, so there are more Brazilian Portuguese speakers worldwide.
Brazil is more respected in the world.
Favorable ocean currents
Trade influences culture regardless of distance.
Groups of people or countries that work together are called Alliance
Colonies provided cheap labor