Which nations are on the security council and why were they chosen as members?

There are five permanent and ten temporary members of the UN Security Council. The states sitting on the security council as permanent members are USA, UK, France, Russia and China, all of which retain the right to veto any action before the Security Council. The remaining ten members of the Security Council rotate between other UN member states. This setup is largely a function of the geopolitics in the immediate period following the end of WWII: the five permanent members were the most powerful states and were on the victorious side of the War.