(a)        State the purpose of each of the following units in a vehicle cooling           system:
            (i)         water pump;
            (ii)        thermostat;
            (iii)       radiator pressure cap.

(b)        State two reasons why water cooling is widely used in motor vehicles.

(c)        State two causes of overheating in a water-cooled engine.

(d)        Name one other cooling system used in motor vehicle.