Which country has the largest population in Southern Europe?

What is the second most populous country in Southeast Asia? Which country is the most populous in West Africa? Which is the third most populous country in the world? Which country is the most populous in Central Europe? What is the most populous country in the European Union? What is the most populous country in the Commonwealth of Nations? Which country is the most populous in the Organization of American States? Which country is the most populous in the Baltic states?