In the figure 12.

(i) From the figure it is observed that EF is the intersection between faces EFGH and EFBA.

The edge EF is highlighted in figure:

(ii) From the figure it is observed that faces EFBA and FBCG intersect at edge FB.

Faces are highlighted in the given figure:

(iii) The three faces which form the vertex A are ABFE, ABCD and ADHE.

Faces are highlighted in the given figure:

(iv) Vertex D is formed by the faces ABCD, ADHE and CDHG.

D is highlighted in given figure:

(v) The edges which are parallel to edge AB are:

CD, EF and HG.

The edges are highlighted in given figure:

(vi) The edges that are neither parallel nor perpendicular to edge BC are AE, EF, GH and HD.

The edges are highlighted in given figure:

(vii) The edges that are perpendicular to edge AB are as follows AE, BF, AD and BC.

The edges are highlighted in given figure:

(viii) A, B, G and H are four vertices that do not all lie in one plane.

The vertices are highlighted in given figure: