VISION QUESTION

(a) The human retina contains two types of photoreceptor cells, rod cells and cone cells.
(i) What is the name given to the region of the retinal that contains the highest density of cone cells 

(1)

 

(ii) Describe how a rod cell reacts to light and causes an impulse to be transmitted through the optic nerve.

(5)

 

(iii) Explain the way in which cone cells allow us to see colour

(4)

 

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