Figure 31.5 Use the Graphs in Figures 31.4 and 31.5 and the and the Following

Figure 31.5
Use the graphs in Figures 31.4 and 31.5 and the following information when answering the corresponding questions.
Canadian and Swiss researchers (van der Heijden et al. ,1998) ,interested in factors affecting biodiversity,grew a variety of grassland plants in combination with one of four arbuscular mycorrhizal (AMF) species,no AMF,or all four AMF species together;and they measured plant growth under each set of conditions.All plant species were grown in each plot,so they always competed with each other with the only difference being which AMF were present.Use the graphs in Figure 31.5 to answer the questions that follow.Note that the x-axis labels indicate the number and identity of AMF species (bar 0 = no fungi;bars A-D = individual AMF species;bar A+B+C+D = all AMF species together) .The y-axis indicates the amount (grams) of plant biomass for the species shown in italics above each graph.Graph (e) is the total biomass (grams) of all 11 plant species combined;graph (f) is the biomass of Bromus erectus plants only,separated from the total.


Figure 31.4 Figure 31.5
-Based on graphs (e) and (f) in Figure 31.5,which is the most well-supported prediction for the effect on total plant biomass if AMF diversity were increased to eight species?

A) No effect is predicted,because the dominant species is unaffected by AMF diversity.
B) Total biomass for eight species would double in comparison to that for four species.
C) Rare species would produce more biomass compared to the case when fewer AMF are present.
D) No effect is predicted,because the dominant species is non-mycorrhizal.