Which type of floral arrangement component is used primarily for structure and framework?

Line flowers are primarily used for structure and framework in floral arrangements. They are characterized by their tall, strong stems and are often arranged in a linear fashion. This structural role helps to create the overall shape and outline of the arrangement, guiding the eye and leading to a balanced composition. Line flowers typically include varieties such as delphiniums, gladiolus, and snapdragons, which contribute height and vertical interest.

In contrast, mass flowers fill the design and add color, while filler flowers are used to fill in gaps and provide a softer texture, which supports the overall look but does not establish the arrangement's structural framework. Form flowers can also add to the design through their unique shapes but focus more on visual interest rather than providing the underlying structure. Thus, line flowers are essential for establishing the foundational layout, making them the correct choice.