5.1.14+Describe+how+trees+operate+logically+(both+binary+and+non-binary)

A binary tree is a tree data structures in which each node has at most two child nodes, usually distinguished as "left" and "right". Nodes with children are parent nodes, and child nodes may contain references to their parents. Outside the tree, there is often a reference to the "root" node (the ancestor of all nodes), if it exists. Any node in the data structure can be reached by starting at root node and repeatedly following references to either the left or right child. A tree which does not have any node other than root node is called a null tree. In a binary tree, a degree of every node is maximum two. A tree with n nodes has exactly n−1 branches or degree.

A simple binary tree of size 9 and height 3, with a root node whose value is 2. The above tree is unbalanced and not sorted.

A non-binary, or multifurcating, tree is a tree in which at least one node has more than two children. Such nodes are referred to as polytomies, or non-binary nodes. A polytomy can have several meanings. In Notung, polytomies are represented as vertical edges with more than two children.