Answer:
HYDROSPHERE
Explanation:
The lithosphere is the solid outer portion of earth. It includes the crust and a small portion of the upper mantle. The rocks present in this region are determined which are hard and undergoes deformation due to the stress that acts on it. The region has been explored and sufficient data has been acquired.
The atmosphere is defined as the gaseous envelope that surrounds the earth. The different layers of atmosphere has been constructed depending upon its height and temperature. The composition of atmosphere is also identified that are present in a definite amount. This amount can either increase or decrease due to the changes in the earth's surface.
The biosphere is the region that includes the hydrosphere, atmosphere and lithosphere where life occurs and interacts between them. Sufficient study has been made regarding this zone and were able to understand how life occurs depending upon the various factors.
The hydrosphere refers to all the water bodies on earth, including the glaciers and the ice bergs.
The terrestrial areas have been explored easily because it is possible for a person to visit those sites but it is not possible to go at a deeper depth to study the structure and the components of the deep water bodies. Although, much of the information has been regarding this sphere, but still the deep water portion such as the deep sea trenches are yet to explore. It is not possible because at this depth, the pressure is extremely high and lift is normally difficult to exist at this pressure condition. But there are some animal and plant species that can grow and survive at this condition.
So, much more is needed to study regarding the hydrosphere.
