What part of a Dutch style greenhouse provides structural support?

The correct answer highlights the function of the purlin, which is a crucial component in the framework of a Dutch style greenhouse. Purlins are horizontal beams that run parallel to the roof slope and are attached to the roof trusses. They are essential for supporting the roof and distributing the weight of the roof materials, as well as any snow or plants that may be on top of the structure. Purlins add stability and strength, ensuring that the roof maintains its shape and can withstand external forces.

In a Dutch style greenhouse, the roof truss primarily acts as a structural support system that bears the overall weight of the roof structure. While both purlins and roof trusses play critical roles in providing support, the purlin specifically serves as a direct reinforcement that improves the roof's integrity. The gutter helps with water drainage, and the end wall provides lateral support and protects the greenhouse from wind, but it is the purlin that actively works within the roof system to maintain structural stability.