Short answers, pulled from the story.
The word geopolitics first appeared in English print in 1902. It was coined by the Austro-Hungarian historian Emil Reich who published his book Foundations of Modern Europe in England two years later to introduce this new vocabulary for describing how geography shapes political power.
Alfred Thayer Mahan believed that national greatness depended entirely on control of the sea. His framework emphasized choke points, canals, and coaling stations as essential elements of naval strategy while proposing six conditions required for a nation to possess true sea power including advantageous geographical position and a society with an aptitude for commerce.
German Geopolitik was discredited by its misuse in expansionist policy during World War II and never achieved standing comparable to pre-war periods. The negative association between classical geopolitics and Nazi or imperialist ideology remains strong particularly in U.S. academic circles despite Bassin revealing in 1987 that Karl Haushofer failed to incorporate racial ideology into his work.
Zbigniew Brzezinski formulated his geostrategic chessboard doctrine aiming to prevent unification of Eurasia. He confirmed that cumulatively Eurasia's power vastly overshadows America's resources and population while his book states its purpose is formulation of a comprehensive and integrated Eurasian geostrategy.
French geopolitical doctrines broadly opposed German Geopolitik by rejecting fixed geography as a determinant of political outcomes. Élisée Reclus considered geography not unchanging but evolving commensurately with human society development while Jacques Ancel published Géopolitique in 1936 at the European Center of the Carnegie Endowment for International Peace in Paris to reject German determinist views including Haushofer's doctrines.