a' path from n, to nk:: =a(unique) sequence of nodes n1,n2,……, nk such that n; is the parent of n;+ for Isi<k o' length of path: number of edges or⑥⑥⊙⑤ the path o depth of n; :=length of the unique path from the root to n Depth(root=0 a' height of n; : := length of the longest path from n, to a leaf Height(leaf)=0, and height(D)=2 o' height (depth) of a tree : height(root)=depth (deepest leaf) o' ancestors of a node: = all the nodes along the path from the node up to the root. descendants of a node: =all the nodes in its subtreesA B C D E F G H I J K L M  ancestors of a node ::= all the nodes along the path from the node up to the root.  descendants of a node ::= all the nodes in its subtrees.  depth of ni ::= length of the unique path from the root to ni . Depth(root) = 0.  height of ni ::= length of the longest path from ni to a leaf. Height(leaf) = 0, and height(D) = 2.  height (depth) of a tree ::= height(root) = depth(deepest leaf).  path from n1 to nk ::= a (unique) sequence of nodes n1 , n2 , …, nk such that ni is the parent of ni+1 for 1  i < k.  length of path ::= number of edges on the path