Question

Which of the following statements about rods and cones is true?
A) Rods are responsible for photopic vision and cones are responsible for scotopic vision
B) Rods are responsible for scotopic vision and cones are responsible for photopic vision
C) Rods and cones both are responsible for photopic vision
D) Rods and cones are responsible for scotopic vision

Answer 1

Hint: 1.Rods provide vision during dim light or night.
2.Cones provide vision during day time or at bright time.

Complete answer:
Rods and cones are the photoreceptors of our eye.
When these receptors are excited by right rays, signals are transmitted first through successive layers of neurons within the retina itself then to the optic nerve and finally to the visual cortex. Each rod and cone is divided into an outer segment, inner segment including nucleus and synaptic body.
Rods and cones are unevenly distributed. The density of rods exceeds that of the cones, except in the fovea where the cone density is highest. The central region of the fovea is even rod-free.
The rods and cones are organized in a fairly exact mosaic. In fovea, the mosaic is a hexagonal packing of cones alone. Outside the fovea, the rods break up the hexagonal packing. The high density of cones and one's relationship with bipolar and ganglion cells account for the highest visual acuity in fovea.
Each cones contain one of three pigments sensitive to either red, green or blue.

Hence, the correct answer is option (B)

Note: Many rods cells converge onto a signal ganglion cell. This makes the rods system a better light detector. The one to one mapping within cones maximizes the discriminations of the details.