Which sphere contains all ecosystems and living organisms on Earth?

The biosphere is the correct choice because it encompasses all ecosystems and living organisms on Earth. It represents the global sum of all ecosystems, including land, water, and the atmosphere, where life exists. This sphere interacts with the geosphere (which includes the Earth's solid parts), the atmosphere (the layer of gases surrounding the planet), and the hydrosphere (which consists of all water bodies). The biosphere is crucial for sustaining life, as it provides habitats, resources, and inputs like oxygen and nutrients that living organisms need to survive.

The geosphere refers to the Earth's rocky components, which do not include living organisms. The atmosphere, while essential for supporting life by providing air, is primarily the layer of gases around the planet rather than the organisms themselves. The hydrosphere includes all water-related components, such as oceans, lakes, and rivers, but again, it does not encompass the living organisms. Therefore, only the biosphere integrates all aspects of life and ecosystems globally.