Answer
In the 2D photograph objects have only height and width with no depth. The objects in the photograph are flat too. The objects in the 3 D scene have height, width and depth.
Step-by-step explanation
The objects in the 2D photograph appear to only have height and width. In the real world scene (3D), the objects captured have a depth. In order to achieve a 3D scene using a 2D object, one should introduce a linear perspective to make all the 2D objects appear 3-dimensional.