Which of the Following Observations Were an Outcome of Studies

Multiple Choice

Which of the following observations were an outcome of studies by David Tilman and coworkers at Cedar Creek,Minnesota on ecosystem stability? Check all that apply.

A) Plots with more species showed less year-to-year variation in biomass.
B) Species-rich plots were less affected by drought than species-poor plots.
C) Over-yielding was observed in more recent work at Cedar Creek.
D) Nitrogen uptake and total biomass produced were negatively correlated to species richness.
E) More diverse plots were less susceptible to invasion by new species.