INSIGHT UPSC QUIZ

ANS. (A) 
An ecosystem is a community of living organisms (plants, animals and microbes) in conjunction with the non-living components of their environment (things like air, water and mineral soil), interacting as a system. These components are regarded as linked together through nutrient cycles and energy flows. They are biological system in the sense that they represent recurring groups of biological community’s supercontinent. It existed from approximately 510 to 180 million years ago. It included most of the landmasses in today’s Southern Hemisphere, including Antarctica, South America, Africa, Madagascar and the Australian continent, as well as the Arabian Peninsula and the Indian subcontinent, which have now moved entirely into the Northern Hemisphere.