Advantages of O2 concentrators for home O2 therapy include which of the following? 1. Operate at safe low pressures. 2. Are cost-effective for continuous use. 3. Do not waste or lose any O2. 4. Can power most pneumatic equipment

a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

ANS: B
Table 56-3 summarizes the major advantages and disadvantages of each system.