Which of the following animals has only rods in its eyes?

The area of the retina that is most sensitive to light is the:

In myopia,light rays from far-off objects converge:

The cornea and lens of the mammalian eyes are both

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.

The choroid is thin over the posterior two-thirds of the eyeball,but it becomes thick in the anterior part to form the: