The Extinction Vortex

The extinction vortex

A) is what happens as a population decreases and becomes more vulnerable to extinction from a variety of causes.
B) is what happens in certain areas,similar to the Bermuda Triangle situation.
C) is what happens when competing species fight over a single niche,often driving both species to extinction.
D) is a spiral of events that occur once a species has become overcrowded through excess reproduction.
E) is a spiral of events that includes introduction of competing species,overexploitation,and disease,in that order.