The infix expression A + B * C, respecting operator precedence, is equivalent to which postfix expression?

The postfix (Reverse Polish) expression 3 4 + 5 * evaluates to:

Which data structure is most suitable for implementing recursion at the machine level?

A stack can be used to check whether a string of parentheses is:

Which data structure would most efficiently implement an undo feature in a text editor?

Which data structure uses the Last-In-First-Out (LIFO) principle?

Which traversal of a binary search tree visits nodes in ascending sorted order?