Mechanical problems since they can be solved and have the second most deaths. I would have the plane go through at least 3 examinations before boarding then one passenger exam before takeoff.
That you are so upset/sad you basically go crazy
An introduced species is a non native species that has one way or another been integrated into the native environment by human or other means.
An invasive species on the other hand is an introduced organism that has become detrimental to the local environment.
