What is the worst-case time complexity for searching for an element in a Binary Search Tree with 'n' nodes, and under what condition does it occur?

What are the worst-case time complexities for a search operation in a standard Binary Search Tree (BST) and a self-balancing AVL tree, respectively, where 'n' is the number of nodes?

If a Binary Search Tree is created by inserting elements that are already sorted in descending order, what will the resulting tree structure look like?

A friend function is not a member of the class(True/False)?

Analyze this destructor implementation:

Person::~Person() {
    if(childrenList != nullptr) {
        delete childrenList;  // Note: delete, not delete[]
    }
}
What is the primary issue with this code?