The muscles surrounding the pupil of a rabbit's eye are:

Analogy type question:
$(1)$ Photoreceptor cells : Cones : Dim light vision : ........
$(2)$ Eyeball contains transparent crystalline : Lens : : In front of the lens : .........

Good vision depends on adequate intake of carotene-rich food. Select the most appropriate option from the following statements.
$I.$ Vitamin $A$ derivatives are formed from carotene.
$II.$ Photopigments are embedded in the membrane discs of the outer segment.
$III.$ Retinal is a derivative of Vitamin $A$.
$IV.$ Retinal is a part of all photopigments that absorb light.

Ciliary muscles are found in

The cornea and lens of the mammalian eyes are both

The density of the vitreous humour is approximately equal to that of the: