Finding Unprotected Pieces

In your quest to checkmate the enemy king, it is helpful to capture your opponent's pieces while minimizing the loss of your own.  As such it is critical that you develop the ability to always quickly recognize which pieces are under attack in any chess position.   

Below I first show some examples of positions featuring good moves that facilitate capturing an enemy piece.  Next I have puzzles in which you must find the best move, taking advantage of your opponent's negligence.

Now you try