?

Contrast is an important principle of design, usually used to emphasize certain elements and draw attention. Forms, in particular, can be designed using the principle of contrast to make them easier to use and understand. But which one of the following forms is not based on the principle of contrast?

1. Drop-down Form – A drop-down form uses contrast to make it easier to differentiate between options, such as color, size, and shape. Contrast is used to highlight the chosen selection from the list of available options.
2. Checkbox Form – Similarly, a checkbox form also uses contrast to separate individual elements from a list of available options. By using contrast, users are able to identify and choose the options that best suit their needs.
3. Radial Form – A radial form uses contrast in the form of a circle or disc to house a set of options from which a user can choose. This form of contrast allows the user to easily find and navigate through the options available within the interface.
4. Textbox Form – Contrary to the forms above, a textbox form does not rely on contrast to help the user differentiate between options. Instead, a textbox form uses text to identify the options from which the user can choose. There is no visual element to it that adds contrast.

Therefore, the Textbox Form does not use the principle of contrast. This form relies instead on text to differentiate the available options. Although contrast is not used, textbox forms can still provide an intuitive and easy-to-use interface for users.