In this unit you will find the handwritten notes of data structures for the topic Basic terminology used with tree,Binary tree, Binary Trees, Binary Tree Representation: Array Representation and Pointer (Linked List) Representation, Binary Search Tree, Strictly Binary Tree, Complete Binary Tree, An Extended Binary Trees. Tree Traversal algorithms: In-order, Pre-order and Post-order. Constructing Binary Tree from given Tree Traversal, Operation of Insertion, Deletion, Searching & Modification of data in Binary Search tree, Binary Heaps, Heap sort, Threaded Binary trees, Traversing Threaded Binary trees, AVL Tree, B-Tree.