Photosensitive compounds are formed of which substances?

Chief functions of the rods and cones in the eye of a vertebrate are

The pigmented layer of the eye is called the .....

Daylight (photopic) vision and colour vision are functions of $P$,while twilight (scotopic) vision is a function of $Q$.
$\quad\quad \quad P\quad\quad\quad Q$

Select the correct option for the blind spot.

The vitreous humor is a jelly-like substance found in the posterior part of the ........