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11.

Mammalian eyes have remarkable power of accommodation by:

A.	Having well developed protractor lentis muscles	B.	Capability of changing the size of eye ball
C.	Capability to change the convexity of lens which changes its focal length	D.	None of these

12.

At rest the mammalian eye is focused for distant objects by:

A.	Relaxation of ciliary muscles which flattens the lens and enables it to have maximum focal length	B.	Contraction of ciliary muscles which makes lens maximum convex
C.	Relaxation of ciliary muscles which makes the lens maximum convex	D.	Contraction of ciliary muscles that makes lens flattened

13.

When the near objects are to be focused by our eye then the:

A.	Ciliary muscles are relaxed and lens is flattened to have maximum focal length	B.	Ciliary muscles are contracted and lens becomes maximum convex
C.	Ciliary muscles are relaxed and the lens becomes maximum convex	D.	Ciliary muscles are contracted and the lens becomes flattened

14.

Duration of temporary blindness on going suddenly from brightness to dark and vice-versa in our eyes is for:

A.	1-2 seconds	B.	2-5 seconds
C.	5-10 seconds	D.	10-30 seconds

15.

Visual pigment in the rods of our eyes is:

A.	Rhodopsin	B.	Iodopsin
C.	Both (a) & (b)	D.	None of these

16.

Visual pigment in the cone cells of our eyes is:

A.	Iodopsin	B.	Rhodopsin
C.	Both (a) & (b)	D.	None of these

17.

Cone cells in our eyes are of three types for three basic colours namely:

A.	Red, green and blue	B.	White, orange and yellow
C.	Red, orange and violet	D.	None of these

18.

In bright light rhodopsin:

A.	Disappears or is reduced	B.	Breaks into opsin and retinine
C.	Is resynthesized	D.	Breaks into scotopsin and iodopsin

19.

The disappearance of rhodopsin is an adaptation in:

A.	Nocturnal animals	B.	Diurnal animals
C.	Both (a) & (b)	D.	None of these

20.

The reformation of rhodopsin is an adaptation in:

A.	Nocturnal animals	B.	Diurnal animals
C.	Both (a) & (b)	D.	None of these