Explain the following terms: (i) Libero (ii) Screening

(i) Libero: a specialised defensive player who wears a jersey of a different colour, may replace any back-row player without a substitution, and cannot serve, block or attack the ball above the net height. (ii) Screening: a fault in which the players of the serving team prevent the opponents from seeing the server or the path of the ball by standing close together, waving the arms or jumping; the point goes to the opponents.