Answer these questions with your own words. Be precise.

1. Does the fact that A* is ``optimally efficient'' mean that A* will never expand more nodes than any other algorithm?
2. Why any node in the frontier with f(n) < f*(n) (the cost of the optimal solution path) will eventually be selected for expansion by A*?
3. Is it true that all admissible heuristics are equal in the sense that A* will search the states in the same order no matter what the heuristic is?