The correct answer is option D, Biosphere
Reason -
Biosphere consists of living beings such as animals, plants, insects, etc which need essential element for their survival and these essential elements are found in all other spheres except the biosphere. The living being needs the following spheres-
a) An species which is living in biosphere and needs water for inheritance has to interact with the hydrosphere.
b) An species which is living in biosphere and needs air for inheritance has to interact with the atmosphere
c) An species which is living in biosphere and needs land for accommodation has to interact with the lithosphere
Thus it is clear that biosphere serves as the interface between different spheres.
