Was sind die Grundprinzipien der österreichischen Bundesverfassung?

Why this is the correct answer

Austria's Federal Constitution rests on five core structural principles: democracy, which vests power in the people; republicanism, which excludes monarchy; federalism, which divides power between the federal and state levels; the rule of law (Rechtsstaat), which subjects all state action to legal norms; and separation of powers, which distributes authority among legislative, executive, and judicial branches. These principles are so fundamental that changing any of them requires a mandatory national referendum. Together they form a framework that cannot be dismantled by ordinary parliamentary majorities.