Depending on the shading of the face, the expressions can drastically change, as well as how people perceive the structure of the face to look like.
Take the last face and compare it to the middle face. The last face looks rounder, but also as if it's mad. Looking at the middle face, The jaw is defined more, and the expression compared to the last face is softer. Compare all of these faces to the first face, and the first face's shape is way more defined than the others. Shading is seen on both sides of the face, giving it more depth.
hope this helps you get a good grade lol
