A list of steps involved in mechanism of vision is given below in a random order.
(i)Neural impulses are analysed and image formed on retina is recognised by visual cortex.
(ii)Membrane permeability changes
(iii)Ganglion cells are excited
(iv)Bipolar cells are depolarised
(v)Action potentials (impulse) are transmitted by optic nerves to visual cortex.
(vi)Potential differences are generated in the photoreceptor cells.
(vii)Light energy causes a change in shape of rhodopsin, leading to the dissociation of retina (an aldehyde of vitamin A ) from opsin (a protein)
(viii)Structure of opsin is changed.
Which of the following options represents these events in a correct order ?

Options

A. (i),(ii),(iii),(iv),(v),(vi),(vii),(viii)
B. (viii),(vii),(vi),(v),(iv),(iii),(ii),(i)
C. (i),(iv),(iii),(ii),(vii),(viii),(vi),(v)
D. (vii),(viii),(ii),(vi),(iv),(iii),(v),(i)

Explanation

To determine the correct order of steps involved in the mechanism of vision, we can analyze the provided steps and arrange them logically based on the physiological processes that occur when light hits the retina. Here’s a step-by-step breakdown:

### Step-by-Step Solution:

1. **Light Energy Activation**: The process begins when light energy causes a change in the shape of rhodopsin, a photopigment found in the photoreceptor cells (rods and cones) of the retina. This step is represented by:
- **(vii)** Light energy causes a change in shape of rhodopsin, leading to the dissociation of retinal (an aldehyde of vitamin A) from opsin (a protein).

2. **Change in Opsin Structure**: Following the dissociation of retinal, the structure of opsin changes, which is the next step:
- **(viii)** Structure of opsin is changed.

3. **Membrane Permeability Changes**: The change in opsin structure leads to changes in the permeability of the photoreceptor cell membranes:
- **(ii)** Membrane permeability changes.

4. **Generation of Potential Differences**: As a result of the change in membrane permeability, potential differences are generated in the photoreceptor cells:
- **(vi)** Potential differences are generated in the photoreceptor cells.

5. **Depolarization of Bipolar Cells**: The changes in potential lead to the depolarization of bipolar cells, which are intermediaries between photoreceptors and ganglion cells:
- **(iv)** Bipolar cells are depolarised.

6. **Excitation of Ganglion Cells**: The depolarization of bipolar cells excites the ganglion cells, which are responsible for transmitting visual information:
- **(iii)** Ganglion cells are excited.

7. **Transmission of Action Potentials**: The excited ganglion cells generate action potentials, which are transmitted via the optic nerves:
- **(v)** Action potentials (impulse) are transmitted by optic nerves to visual cortex.

8. **Recognition of Image**: Finally, the neural impulses are analyzed, and the image formed on the retina is recognized by the visual cortex:
- **(i)** Neural impulses are analysed and image formed on retina is recognised by visual cortex.

### Correct Order of Steps:
The correct order of the steps involved in the mechanism of vision is:
1. (vii)
2. (viii)
3. (ii)
4. (vi)
5. (iv)
6. (iii)
7. (v)
8. (i)