Why did the marriage of ferdinand to isabella unify spain

Which of the following allowed the government to stop a foreigner from becoming a citizen, presidential power to throw anyone he wanted out of the u.s. and that it was a crime to criticize the government? the alien and sedition act the xyz affair the 12th amendment marbury v madison

What roles does climate change and natural resources play in global politics?

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?