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:0008219
cell death
node5->node6
node7
GO:0012501
programmed cell death
node6->node7
node8
GO:0006915
apoptotic process
node7->node8
node9
GO:1990009
retinal cell
apoptotic process
node8->node9