Which type of tree node has no children?

A node in a tree structure is a fundamental unit that can represent various elements. In this context, the specific type of node known as a leaf node is defined as one that has no children. Leaf nodes are typically located at the ends of branches in a tree and are crucial for representing terminal points in data structures such as binary trees, search trees, and so on.

Nodes classified as "parent" have at least one child node connected to them, while a "root" node is the topmost node in a tree structure, which has children (unless the tree is empty). Therefore, the defining characteristic of a leaf node—having no children—makes it the correct answer in the context of tree nodes.