Consider the following tree:   Node 5 is a [ Select ] ancestor parent sibling child of node 3. Node 9 is an [ Select ] leaf internal node. Node 8 is a [ Select ] sibling child ancestor descendent parent of node 1. Node 3 is the [ Select ] child descendent sibling parent of node 8. Node 8 is a [ Select ] leaf internal node. Node 10 is a [ Select ] ancestor sibling descendent parent child of node 2. Node 1 is an [ Select ] ancestor child sibling descendent parent of node 6. The relationship beween nodes 10 and 9 is [ Select ] siblings parent-child they are unrelated . Node 9 is at level [ Select ] 3 0 2 1 of the tree. The height of this tree is [ Select ] 5 3 4 2 .      多重下拉选择题