The main function of the colonists' committees of correspondence was spreading the news of the Boston massacre and gaining support of the people around the world against the British. This Committees of Correspondence was created by the Patriots of America. I hope the answer helps you.
Based on my knowledge, the scramble for Africa was largely because the industrial revolution was springing up all over the world in largely European countries and they were at a point where resources were running out. Gold and other valuable metals were discovered in Africa as well as timber. The surplus of resources in Africa made it very valuable to these industrial countries so they all made a huge "scramble" to Africa. Also, the idea of merchantilism, the idea that the amount of land a country owned defined its wealth, was still very popular so these countries wanted to make a huge land grab.
Which is based on the Supremacy Clause, federal law preempts state law, even when the laws conflict. Thus, a federal court may require a state to stop certain behavior it believes interferes with, or is in conflict with, federal law.