They really help in the process of Africa's state building, creating commercial networks between parts of the continent, and introducing literacy ( especially on northern part of Africa)
They also controlled the sea route between Asia and Africa and managed to maintain the relationship between Africa and the middle east
China and Japan I hoped this helped :)
Converging plate boundaries. continent to continent plate boundary converging if you want to be more specific.
to converge means to bring something together, that's how I always remembered. Transform boundaries move side to side, and are the reason for mainly fault lines, such as the San Andreas Fault in California. All plate boundaries do occur at subduction zones.