A group of scientists conducted an experiment to determine if a symbiotic fungi (endophyte) affected the health of cacao plants that were infected with pathogenic bacteria. Hall of the cacao seeds received the endophyte, and the other half did not. All plants were infected with bacteria and monitored for leaf damage. The results are shown in the graph below
Results
Endophyte not present; pathogen present ( E - P +) Both endophyte and pathogen present (E+P+)
30
20
10
0
E-P+
15
10
5
Leaf mortality (%)
0
E+P+
Leaf area damaged (%)
E-P+
E+P+
Data from A. E. Arnold et al., Fungal endophytes limit pathogen damage in a tropical tree, Proceedings of the National Academy of Sciences 100:15649-15654 (2003).
Which conclusion is supported by the results of this study?
(1 point)
The endophytes have a neutral effect on the tree's growth
The endophytes have a parasitic effect on the cacao trees
The endophyles Incnsase the trees immunity against the pathogen
The endophytes perform photosynthesis when the trees lose their leaves.