Gravity!
Gravity is the natural downward force, proportional to mass. Gravity is strongest at Earth's surface.
There are couple of characteristics that all fungi have:
1) They all the "Heterotroph"
2) They all have "Chitin" on their cell walls
Hope this helps!
I would hazard a guess to say that they aren't as good at it because they don't need to be. In lakes and even the ocean, the state of the environment would stay relatively constant negating the need for homeostasis or regulating salt levels.
He should drink the orange juice