I’m sorry i just have to put in answers so i can ask a question
The answer is c. His father has grown quite ill in david's absence and needs hep.
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.
