test
node1
GO:0009605
response to external
stimulus
node2
GO:0009991
response to
extracellular
stimulus
node1->node2
node6
GO:0031667
response to nutrient
levels
node2->node6
node3
GO:0008150
biological_process
node4
GO:0050896
response to stimulus
node3->node4
node4->node1
node5
BFO:0000015
process
node5->node3
node7
GO:0006791
sulfur utilization
node6->node7
node8
BFO:0000003
occurrent
node8->node5
node9
BFO:0000001
entity
node9->node8