What significant aspect of "Casa Mila" contributes to its organic form?

The use of sculptural modeling of limestone is a significant aspect that contributes to the organic form of "Casa Mila," also known as La Pedrera, designed by Antoni Gaudí. This technique allows for fluid, undulating shapes that mimic natural forms, eschewing traditional straight lines and rigid structures. Gaudí’s approach was inspired by the natural landscape, and the limestone's textural qualities enable the building to reflect the rhythms and forms of nature, enhancing its organic aesthetic.

Unlike typical architecture that often adheres to geometric symmetry or straight lines, "Casa Mila" incorporates curved shapes and natural motifs, making it seem as if the building is a natural extension of the earth. This fluidity is crucial to its character, as it integrates seamlessly with its surroundings.

The other choices, such as the use of bright colors or symmetry in design, do not encapsulate the essence of organic form as effectively. The focus here is on the material and form itself rather than color or traditional layout, which reinforces the distinction of "Casa Mila" as a unique architectural masterpiece.