According to most conservation biologists, the single greatest ...

[penza]

According to most conservation biologists, the single greatest threat to global biodiversity is
A) chemical pollution of water and air.
B) stratospheric ozone depletion.
C) overexploitation of certain species.
D) alteration or destruction of the physical habitat.
E) global climate change resulting from a variety of human activities.

[plus1]

I recall doing this last year, it's D, bye bye!

[penza]

Perfect, answer was correct