Countries Closest to the Equator but Don't Touch It

Name the body of water that separate each two places.

Name the countries where the most people speak Russian as their native language.

Name all the countries in the world that are either inside the Arctic Circle, or can reach it by sailing due north and not hitting any other country on the way.

Which countries have the furthest possible distance between two points that are part of the country - including all their overseas possessions?