In design, the relationship between parts in size and structure is known as?

The correct answer is proportion because it specifically refers to the relationship between different elements in a design regarding their size and structure. Proportion helps to create a sense of balance and harmony within a design, influencing how components relate to one another and to the overall design as a whole. Designers consciously manipulate proportion to achieve aesthetic appeal and to ensure that different parts complement rather than overwhelm each other.

Emphasis refers to creating a focal point within a design, directing attention to specific areas rather than discussing the relationship between sizes. Intensity typically relates to the vividness or saturation of a color, which does not pertain to size or structure. Shade, on the other hand, refers to variations in color created by adding black or darkening elements, which also does not involve a relationship between the sizes of different parts in a design.