int avl(binarysearchtree root): if(not root) return 0 left_tree_height = avl(left_of_root)  if(left_tree_height== -1) return left_tree_height  right_tree_height= avl(right_of_root)  if(right_tree_height==-1) return right_tree_heightDoes the above code can check if a binary search tree is an AVL tree?  *2 pointsyesno

The given code appears to be written in a programming language. It defines a function named "avl" that takes a parameter called "root", which is expected to be a binary search tree. The function checks if the binary search tree is an AVL tree.

Here is a step-by-step breakdown of the code:

1. The function starts with a check for a null root. If the root is null, it means there is no tree, so the function returns 0.

2. If the root is not null, the function recursively calls itself on the left subtree of the root and assigns the returned value to the variable "left_tree_height".

3. Next, the code checks if the "left_tree_height" is -1. If it is, it means that the left subtree is not balanced, and the function returns -1.

4. If the left subtree is balanced, the code proceeds to recursively call itself on the right subtree of the root and assigns the returned value to the variable "right_tree_height".

5. Similar to step 3, the code checks if the "right_tree_height" is -1. If it is, it means that the right subtree is not balanced, and the function returns -1.

6. If both the left and right subtrees are balanced, the function does not return -1 at this point. This suggests that the binary search tree is an AVL tree, and the function can return a value indicating that it is indeed an AVL tree.

Based on the provided code, it seems that the function is designed to check if a binary search tree is an AVL tree.