Answer:
The total number of different species in an area.
Step-by-step explanation:
Bio means relating to life, and diversity means a wide range of different, in this case, organisms.
Biodiversity is describing what exists, not disappearances, or appearances.
So you can rule out:
the rapid disappearance of a species in an area and the rapid appearance of a species in an area.
Diversity means many, so that wouldn't mean just one single species.
Rule out:
the total number of a single species in an area.
That means the total number of different species in an area is the answer.
:)