Question

What system includes the living components of the Earth?

Answer 1

The biosphere is a system and part of the earth's spheres that encompasses all living organisms that thrive and survive in the planet earth. In most  of these organisms, they are comprised of cells. hence cells are the fundamental basis for these  organisms. 

Answer 2

The biosphere and the biotic factors are the system and the factors which include all the living components and living beings of the Earth. The opposite would be the abiotic factors or the non-biosphere which don't represent living components of the Earth.