Question

Match the following columns and select the correct option:

	Column I		Column II
(a)	Rods and cones	(i)	Absence of photoreceptor cells
(b)	Blind Spot	(ii)	Cones are densely packed
(c)	Fovea	(iii)	Photoreceptor cells
(d)	Iris	(iv)	Visible coloured portion of the eye

• A. (a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)
• B. (a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)
• C. (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)
• D. (a)-(ii), (b)-(iv), (c)-(iii), (d)-(i)

Answer 1

The correct option is A (a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)

Cones and rods are two types of photoreceptor cells present in the retina. Cones are responsible for the daylight or photopic and colour vision. The rods are responsible for scotopic vision or night vision.

Photoreceptor cells are not present in a region of the retina called the blind spot.

Fovea is the central pit of the yellowish pigmented spot called macula lutea present at the posterior pole of the eye lateral to the blind spot. It is the portion of the retina where cones are densely packed.

The iris is an opaque and pigmented structure which is the visible, coloured portion of the eye. Iris muscles regulate the diameter of the pupil.

Fig: Human eye