Question

To be three dimensional, a piece of art must have

color
depth
a flat surface
a human actor

Answer 1

As the other person said, depth!

In two dimensional pieces of art, we only see length and height, or how long and tall something is. But we don't see how long it is on the sides. The third dimension adds depth, allowing us to see the whole figure in the image. Hope this helped!

Answer 2

Your answer should be depth

Step-by-step explanation:

If we say a work of art is three-dimensional, we mean that it is fully articulated in space-that is to say it can be viewed from any angle and exists in the viewer's space. Hope this helped :)