In the Grass Park Experiment, Researchers Have Fertilized a Grassland

In the Grass Park Experiment, researchers have fertilized a grassland at the Rothamsted Experimental Station in Great Britain since 1856. Sampling for species diversity through time shows that rank-abundance curves have gotten ________ over time, indicating ________ species evenness.

A) steeper; increasing
B) steeper; decreasing
C) more shallow; increasing
D) more shallow; decreasing
E) Rank-abundance curves have not changed through time.