What is biosphere? what are the main elements of biosphere ?​

The biosphere, also called the ecosphere, is the natural environment of living organ- isms and is the complex biological epidermis of the Earth whose dimensions are not precisely defined. It consists of the surficial part of the lithosphere, a lower part of the atmosphere, and the hydrosphere.

The regions of the surface, atmosphere, and hydrosphere of the earth, occupied by living organisms

Ibelieve that a would be the best answer.