Identifying plane changes in a form is most useful for what?

To place light and shadow correctly

A form is not understood only by its outer outline. Its surfaces, or planes, turn in different directions. When a plane changes direction, it receives light differently from a neighboring plane. Recognizing these changes helps an artist show volume, structure, and the three-dimensional character of the form instead of making it appear flat.

Option B is correct because light and shadow depend on the direction of each plane in relation to the light source. A plane facing the light is generally lighter, while a turned-away plane is generally darker, with gradual or sharp changes where appropriate. The other choices are unrelated: plane changes do not decorate a title, explain paper smell, or make a form flat. They help place values accurately.

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