Fight or flight, because according to Hans Selye, this occurs at times of danger when your adrenaline is heightened.
Intermediate and deep focus earthquakes. The reason is being the tectonics plates are always shifting and so, old it’s always able to cause a problem. The tectonic plates crash at some point. Usually it’s a small one at first, then a big one, and after that a aftershock which is bigger than the second one.
This is the best I can give you right now with a deadline.
The most accurate information would most likely come from source C
The answer will be an ecosytem