What kind of design element often undergoes several iterations before completing?

The choice of a prototype as the correct answer reflects an essential phase in the design process, especially in fields like animation, product development, and user experience design. A prototype is a preliminary version of a product or project that enables designers to explore ideas and validate concepts. It is a tangible representation that stakeholders can interact with, allowing for user feedback and testing.

Prototyping often involves multiple iterations; as designers try out different features, layouts, and functionalities, they gather input from testers and make revisions to improve the product. This iterative process helps ensure that the final product meets user needs and expectations.

In contrast, while sketches and storyboards are also important design elements in the creative process, they typically serve more as initial concepts rather than functioning prototypes. Sketches are often rough representations used to brainstorm ideas, and storyboards outline a sequence of events but do not carry the same level of user interaction and feedback dynamics that prototypes do. Review documents, on the other hand, are assessments of work that has already been completed, rather than a stage that undergoes iterative design changes.