12. Explain a height balanced binary tree. 13. Discuss the improvement in performance of binary trees brought by using threads. 14. Discuss the difference between a general tree and a binary tree. What is a complete binary tree? Give an algorithm for deleting an information value X from a given lexically ordered binary tree. 15. Draw a B-tree of order 3 for the following sequence of keys: 2, 4, 9, 8, 7, 6, 3, 1, 5, 10 16. Consider the following specification of a graph G V(G) = { 4,3,2,1 } E(G) = {( 2,1 ),( 3,1 ),( 3,3 ),( 4,3 ),( 1,4 )} (i) Draw an undirected graph. (ii) Draw its adjacency matrix.