The eyes of cat, cow, buffalo and some nocturnal animals shine in the night. It is due to the presence of $tapetum \text{ } lucidum$ between the choroid and retina. This shining is due to the presence of a pigment made of:

Which of the following is a characteristic of the human cornea?

Select the correct option:
$(1)$ There are no photoreceptor cells slightly above the posterior pole of the eyeball,hence it is called the blind spot.
$(2)$ Rod cells contain a purple-red protein called rhodopsin.

Which of the following statements are correct regarding the fovea?
$I -$ The central pit of the macula lutea is called the fovea.
$II -$ The fovea is a thinned-out portion of the retina.
$III -$ The fovea contains densely packed rods.
$IV -$ Visual acuity is highest in the fovea region.

Corneal transplantation is highly successful because:

Which layer of the wall of the eyeball looks bluish in color?