Researchers Tested Nitrogen Loss from Soil Where the Moss Dawsonia

Multiple Choice

Researchers tested nitrogen loss from soil where the moss Dawsonia was growing and compared it to soil from which Dawsonia had been removed. The data are presented in the accompanying figure.
-In the figure, which graph of soil nitrogen loss over time most strongly supports the hypothesis that if the 20-cm-tall Dawsonia acts as a physical buffer, then it reduces water's ability to erode the soil and carry away its nitrogen?

A) A
B) B
C) C
D) D
E) None of these graphs support the hypothesis.