Which of the following properties holds true for a Strictly (or Proper) Binary Tree?
In a Strictly (or Proper/Full) Binary Tree, every node in the tree has either 0 children (leaf nodes) or exactly 2 children (internal nodes).
What is the relationship between the number of leaf nodes (L) and internal nodes with two children ($I_{2}$) in any non-empty Binary Tree?
In any binary tree, the number of leaf nodes (nodes with degree 0) is always exactly one greater than the number of internal nodes with degree 2: $L = I_{2} + 1$.
Given the Preorder traversal (ABDECFG) and Inorder traversal (DBEAFCG) of a Binary Tree, what is its Postorder traversal?
Preorder gives root 'A'. Inorder splits left subtree (DBE) and right subtree (FCG). Reconstructing recursively: Left subtree yields DEB, right subtree yields FGC, root is A -> Postorder is DEBFGCA.
Which data structure is implicitly used during Level-Order Traversal (Breadth-First Traversal) of a tree?
Level-order traversal visits nodes level by level from top to bottom. It uses a Queue (FIFO) to enqueue children of nodes as they are visited.
Which statements correctly describe Level-Order Traversal of a binary tree?
All three statements are correct. Level-order traversal is breadth-first traversal of a tree, and a FIFO queue preserves the order in which nodes are discovered at each level.