Which roof is characterized by a single ridge line from which sections descend at different pitches?

The gambrel roof is distinguished by its unique design featuring two different slopes on each side. This roof style typically has a single ridge line at the top, with one section descending at a steeper pitch and the other section at a shallower pitch. This configuration allows for increased attic space or headroom, making it a popular choice for structures such as barns and certain residential buildings.

In contrast to other roof types mentioned, the butterfly roof features two angled sections that slope towards a central valley, the gable roof is characterized by two slopes that form a triangle at the ridge, and the flat roof has a single horizontal plane without any slopes. Each of these roofing styles has its own specific functionalities and aesthetic appeal, but the distinct pitch variations of the gambrel roof are what set it apart distinctly in this context.