Answer to Question 1
ANS: B
When the water vapor content of a volume of gas equals its capacity, the RH is 100. When the RH is 100, a gas is fully saturated with water vapor.
Answer to Question 2
ANS: D
The BH of a gas is the ratio of its actual water vapor content to the water vapor capacity in saturated gas at body temperature (37 C). Thus BH is the same as RH, except that the capaci-ty (or denominator) is fixed at 43.8 mg/L.