What is mounted at the front and rear of the roof panel?

The correct choice for what is mounted at the front and rear of the roof panel is a glass seal. Glass seals are critical components used in vehicles to provide a secure and weather-tight fit for windows and windshields, especially along the edges where glass meets the body of the car. These seals help to prevent water, dirt, and air from entering the vehicle, ensuring not only a more comfortable ride but also protecting interior components from damage.

In addition to their primary function of sealing, glass seals also contribute to the vehicle's structural integrity by holding the glass in place. Proper installation and maintenance of glass seals are essential in minimizing issues such as leaks, which can lead to rust and damage over time.

Other options like metal brackets, weather stripping, and roof racks serve different purposes. Metal brackets are typically used for structural support or to connect different parts of the vehicle but are not specifically mounted along the roof panel. Weather stripping, although it serves similar functions to glass seals in sealing doors and windows, is not generally associated with the roof panel specifically. A roof rack is an accessory used for carrying cargo; it is not a component that directly seals or supports the roof panel itself.