Question

Why is it difficult to differentiate between red and green color objects in dark or at night?
(a)Rods work well, only during the daytime.
(b)Cones work well, only during the daytime.
(c)Rods work well, only during nighttime.
(d)Cones work well, only during nighttime.

Answer 1

Hint: These photoreceptor cells are not fully functional during dim light. They are of three types based on the wavelength peeking on them- L, M, S types. and are present much less numerous than other photoreceptors cells.

Complete answer:
The retina invertebrate is a light-sensitive portion of eyes which have photoreceptors like cones for day and color vision and rods for night vision. To see the object light must pass through the neural element to strike the light-sensitive photoreceptor rods and cones. In the daytime, in the presence of ample amount of light we can see objects with help of cones which is responsible for the color vision but during night decrease in light makes it difficult to differentiate color objects as rods are highly specialized for night vision.

Additional Information:
-All vertebrates including humans are able to see the color during the daytime because light reflected from the object hits the retina where the special cells known as photoreceptors turn the light into an electrical signal.
-There are two types of photoreceptors in the retinas of the human eye that are cones and rod photoreceptor cells.

-Cones
-These are a specialized cell for day vision present at the back of the eye.
-These cells are low sensitive which contains a low amount of photopigment.
-They are more sensitive to direct light and show fast response which takes short integration of time.

-Rods
-These are specialized cells for night vision present at the back of the eye.
-These cells are highly sensitive which contains more amount of photopigment.
-They are more sensitive to scattered light and show slow response which takes long integration of time.

So, the correct answer is, ‘Cones work well, only during the daytime.’

Note:
 -Night blindness also is known as nyctalopia caused due to deficiency of vitamin A is a condition when a person is not able to see clearly in dim light or darkness.
-Colour blindness is a condition in which the person is not able to see the color in a normal way. It is a genetic disorder.