I believe the question is according to the attached image. The order of the diagram that would show primary succession in an area that had never before been occupied by living organisms is; C,A, B, D. Primary succession occurs in lifeless areas; these are regions in which soil is incapable of sustaining life as a result of factors such as lava flow, newly formed sand dunes, or rocks left from a retreating glacier.
Answer:The world’s glaciers are in retreat. The great tongues of ice high in the Himalayas, the Andes, the Alps and the Rockies are going back uphill at ever greater speeds, according to new research.