Lenses are engineered to have specific focal lengths besides the curvature of two sides of a lens what determines the focal length

I believe the correct answer is: material that the lens is made from.

Lenses are engineered to have specific focal lengths, besides the curvature of the two sides of a lens. The focal range, the distance between your optic nerve and the retins in lens, of the lenses is determined by the material that lenses are made from.

based on the images pictured above, the major difference between the two cathedrals: the cathedral of notre dame and the amiens cathedral, is that the cathedral of notre dame emphasizes the horizontal lines while the amiens cathedral emphasizes the vertical lines.