Which type of greenhouse is a semi-cylindrical structure?

• A. Sawtooth
• B. Lean To
• C. Gutter-connected (Ridge-and-furrow)
• D. Quonset

Answer: (D)

Greenhouse shapes are defined by their cross-sectional profile. A semi-cylindrical structure has a curved, half-round roof created by arches, giving a continuous rounded top. This is exactly what a Quonset greenhouse is: a hoop-style frame bent into a semicircle and covered with plastic or panels, forming a curved, half-cylinder shape. That rounded roof helps distribute wind loads smoothly and allows quick construction.

The other options don’t have a curved, half-circle roof. A sawtooth greenhouse features a jagged, triangular roofline; a lean-to is attached to an existing wall with a single sloped roof; gutter-connected (ridge-and-furrow) consists of multiple bays with a ridge and gutters, producing a long rectangular profile rather than a curved arch.