How many cases of hiv/aids infection exist in the world today?
a. 1.5 million
b. 25 million
c. 33 million
d. 42 million

In order for a high temperature boiler or steam engine to produce superheated water, or steam: the heat source must be greater than 100°c the water must be permitted to evaporate quickly the system must be sealed and become pressurized above atmospheric pressure the vapor pressure must be kept below 760 mm(hg)