Two _____________________ lights in a _________________________ line may be used to indicate that a boat is broken down.

The statement that two red lights in a horizontal line may be used to indicate that a boat is broken down is accurate within the context of maritime navigation and signaling. Red lights are universally recognized in various maritime contexts to convey caution or an indication of distress. When positioned horizontally, they serve as a clear signal to other vessels that the boat is experiencing difficulties and is in need of assistance. This signaling is critical for ensuring safety on the water by alerting nearby vessels to exercise caution and recognize the situation of the distressed boat.

Understanding signaling conventions is essential for safe maritime operations. Using appropriate colors and configurations for signaling can help prevent accidents and facilitate timely assistance to boats in trouble. In contrast, other colors and configurations do not carry the same recognized meaning in this context, highlighting the importance of understanding specified maritime safety protocols.