What is the wide, flat part of a feather, made up of barbs that are hooked together in rows?

The wide, flat part of a feather is known as the vane. This structure is composed of numerous barbs that interlock with one another through tiny hooks, forming a cohesive surface that provides the feather with its necessary aerodynamic properties. The arrangement of the barbs helps create a flat surface, which is crucial for flight, insulation, and waterproofing.

The vane of a feather plays a vital role in its overall function. When structured correctly, it allows birds to generate lift during flight and helps them maintain a streamlined shape. Additionally, the interlocking nature of the barbs ensures that the feather can withstand the forces encountered during flying, while also facilitating easy care, such as preening by the bird. Each of the other options refers to different parts of a feather: the rachis is the central stem of the feather that supports the barbs, the quill is the hollow base that anchors the feather to the bird, and a barb is the individual filament that contributes to the overall structure of the vane but does not comprise the whole flat surface itself.