predator-prey population cycles less biomass at higher levels of the food web a shrinking variety of animal and plant species competition among some consumer populations
I gave my students this multiple choice question: Which of these is a threat to the survival of an ecosystem?

Only one answer is correct among these 4 choices:
- predator-prey population cycles
- less biomass at higher levels of the food web
- a shrinking variety of animal and plant species
- competition among some consumer populations

Could you tell me which one is correct?

a shrinking variety of animal and plant species