The food chain is very important to ecosystems.
I think the answer is a cell..
B.Liquid Water
Explanation: lava gushes out ashes go up and gases when it erupts only water does not erupt.
In aquatic plants, water passes among the tissues and provides the medium for gas exchange. In terrestrial plants, air enters the tissues, and the gases diffuse into the moisture bathing the internal cells.
Hope this helps