Answer:
See the explanation below.
Step-by-step explanation:
a)
Pumping water requires equipment with closed housing, so that water is not irrigated from the pumping point.
Fans in some applications do not require closed housings, as air irritation does not create anomalies or areas of nonconformity at the air pumping point.
b)
The pressures in water pumping equipment are usually much higher than those generated with air equipment, since the density of water is much higher than that of air, almost 1000 times higher.