test
node1
BFO:0000001
entity
node2
BFO:0000003
occurrent
node1->node2
node2->node2
node3
BFO:0000015
process
node2->node3
node4
GO:0008150
biological_process
node3->node4
node5
GO:0009987
cellular process
node4->node5
node6
GO:0140253
cell-cell fusion
node5->node6