Why are both proportion and value necessary to make a form realistic?

Proportion gives structure and value shows volume

The governing concept is that realistic form depends on both accurate structure and believable light. Proportion compares the sizes and positions of parts, so it establishes the object’s shape, balance, and construction. Value means the arrangement of light, middle, and dark tones; it describes how light falls across surfaces and makes volume, turning, and depth visible. Option A is correct because these two systems work together: correct proportion makes the form anatomically or geometrically credible, while value makes it appear solid rather than flat. Options B and C misunderstand proportion, and D is false because value strongly communicates depth and surface direction. When checking a drawing, inspect structure first and tonal modelling next.

This is a Class 9 Art Education question. Chapter: Elements of Art. Topic: Form.