Alexander spread Greek technology and ideas through his empire where people talked and visited from all areas to see what had been done.
The convection currents are the ones that create the force that breaks up and moves the crustal plates on the surface of the planet. By moving the crustal plates, the convection currents contribute to the formation of different types of plate boundaries, including the divergent plate boundaries.
The divergent plate boundaries are the boundaries where two plates are moving away from one another because the convection currents are dictating that kind of movement from bellow them. As they move away from each other, they leave a gap between them, and the convection currents push up a lot of magma towards the surface. The magma cools of very quickly in the water, thus forming rocks constantly, rocks that little by little start to make a big mas, that eventually turns into an underwater mountain, or rather a mid-ocean ridge.
The geography of East Asia is described as mountainous. An example is the geography of west and north China. It is usually dominated with mountains, steppe lands, plateaus, and deserts. I hope my answer has come to your help. God bless and have a nice day ahead!
Some of the negative effect of immigration are
1. Overcrowding ( could increase cost of housing)
2.increasing cost of services such as health care and education
3. Disagreement between different religions and cultures
4. It might stimulate capital formation and increase the level of *brain gain*.
5. Potential fall in real wages,especially for low skilled workers.
I hope this helps