What is a critical load? A) the amount of nutrient augmentation ...

[penza]

What is a critical load?
A) the amount of nutrient augmentation necessary to bring a depleted habitat back to its former level
B) the level of a given toxin in an ecosystem that is lethal to 50% of the species present
C) the maximum abundance level of a particular species, beyond which additional numbers will degrade a habitat
D) the amount of added nutrient that can be absorbed by plants without damaging ecosystem integrity
E) the number of predators an ecosystem can support that effectively culls prey populations to healthy levels

[plus1]

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

[penza]

Thanks so much!