It should be noted that, in most cases, the supply and return ductwork must be attached to the ____ before the unit is set in place.

1. A curb

2. B package

3. C boom

4. D load

 ____ are intended to help provide the correct amount of ventilation and may help reduce cooling costs by allowing outside air to be introduced to the conditioned space when conditions are correct.

1. A Maximizers

2. B Economizers

3. C Re-circulators

4. D Minimizers