Which of the following is a primary component of the Intoxilyzer 9000?

The primary component of the Intoxilyzer 9000 is indeed the control unit. This component serves as the main processing hub of the device, coordinating various functions including data collection, management of the sample analysis, and communication with other components such as the display and power supply. The control unit ensures that the device operates correctly and provides accurate results by executing the necessary algorithms for analyzing breath samples to determine blood alcohol content.

While all other components, such as the display screen, sample analysis software, and power supply unit, play important roles in the operation of the Intoxilyzer 9000, they are considered auxiliary elements. The display screen relays information to the operator, the sample analysis software interprets the data obtained from the breath samples, and the power supply unit provides the necessary electrical energy to operate the device. However, none of these components can function independently without the control unit orchestrating their activities. This central role is what makes the control unit a primary component of the system.