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

The function of the iris is to ....

The condition of 'miosis' of the pupil refers to:

Select the correct option for the mechanism of vision.

At the posterior pole of the eye lateral to the blind spot, there is a yellowish pigmented spot called

Read the following statements with respect to the human eye and select the correct option.
Statement $I$: Uvea is the middle,vascular,and non-pigmented layer of the eye that lies outer to the retina.
Statement $II$: The size of the lens can be adjusted depending on the distance of the object from the eye,through the muscles of the ciliary body and the suspensory ligament.