Answer:
Geosphere or lithosphere took the longest time to form
Explanation:
There are basically four subsystems of planet earth -
a) Geosphere or lithosphere - consists of land mass and all rocky strata
b) Hydrosphere: - Water reserves on earth
c) Biosphere: living things on earth
d) Atmosphere: - Gases around the earth
Out of these four subsystems , the one that took the longest time for changing is Geosphere or lithosphere
Some changes in this subsystem have happened only in a short span of time i.e instantaneouly such as rotation of the Earth, earthquake etc.
While some chnages have taken billion of years such as formation of coal and petroleum, formation of plate tectonics
