What is an example of an abiotic element that may change an area?

Imagine ? person stepping on a pin and pulling his or her foot way look at the réfléchir arc of the scenarios below

It is believed that europa, one of jupiter’s moons has an ocean beneath its surface. based on how earth’s oceans and atmosphere are believed to have formed, what can be said about europa’s supposed ocean? the arrival of in the early days of europa’s existence could have formed its ocean. it is likely that the water experienced , similar to earth. it is also possible that this water is retained beneath europa’s surface and in its atmosphere due to europa’s .

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important