What are the differences between a heap and a binary search tree in terms of their structure and operations?

A heap is a complete binary tree where each node has a value greater than or equal to its children, and it is typically used for priority queue operations like inserting and removing the maximum element. On the other hand, a binary search tree is a binary tree where each node has a value greater than all nodes in its left subtree and less than all nodes in its right subtree, and it is used for efficient searching, insertion, and deletion operations.