Describe how there was a diffusion of crops along trade routes in afro-eurasia

The sahel is located on the edge of the sahara desert. a.north b.west c.south d.east

The system of checks and balances was designed for what purpose? fear of strong state power to keep power out of one branch to appease the southern states to allow the judicial branch to have equal power

The quote below is an excerpt from the charter of the united nations: "the purposes of the united nations are: to maintain international peace and security, and to that end: to take effective collective measures for the prevention and removal of threats to the peace, and for the suppression of acts of aggression or other breaches of the peace, and to bring about by peaceful means, and in conformity with the principles of justice and international law, adjustment or settlement of international disputes or situations which might lead to a breach of the peace . " source:this section implies that the united nations is prepared to do what to keep world peace?