The correct answers are:
A. hurricane
D. Introduction to an aggressive invasive species.
E. Tsunami
A catastrophic events are the events which can cause heavy damage to the ecosystem. Hurricane, a tropical cyclone, tsunami, a series of destructive tidal wave cause heavy damage to the ecosystem. Along with hurricane and tsunami, an aggressive invasive species (a species which is not native to a specific location) which have a tendency to spread very fast to the given geographical location and cause damage to the ecosystem by damaging local species.
