Final answer:
The roommate is using the supportive behavior known as Passive Constructive, showing support for going to the Bengals game together.
Step-by-step explanation:
The supportive behavior being demonstrated by the roommate in this scenario is
Passive Constructive
. Passive Constructive behavior involves providing a positive response or reaction to someone else's ideas or suggestions without actively engaging or contributing further. In this case, the roommate is showing support for the idea of going to the Bengals game and is willing to participate by buying the tickets. This behavior fosters a sense of togetherness and encourages enjoyable experiences with others.