Dark adaptation in human eye includes :

Options

A. Conversion of 11-cis retinene to trans-retinene
B. Conversion of trans-retinene to 11-cis-retinene
C. Decomposition of rhodopsin to retinene
D. Decomposition of rhodopsin to scotopsin

Answer

### Step-by-Step Solution:

1. **Understanding Dark Adaptation**:
- Dark adaptation is the process by which the retina of the human eye adjusts to low light conditions. This involves biochemical changes in the photoreceptors (rods and cones) to enhance sensitivity to light.

2. **Identifying Key Components**:
- The main components involved in dark adaptation are the photopigments in the rods and cones, particularly rhodopsin (in rods) and the forms of retinene (11-cis-retinene and trans-retinene).

3. **Analyzing the Options**:
- **Option A**: Conversion of 11-Cis-Retinine to Trans-Retinine
- This is incorrect. In dark adaptation, we are concerned with the conversion of trans-retinene back to 11-cis-retinene.

- **Option B**: Conversion of Trans-Retinine to 11-Cis-Retinine
- This is correct. During dark adaptation, trans-retinene is converted back to 11-cis-retinene, which is essential for the regeneration of rhodopsin, allowing the eye to adapt to darkness.

- **Option C**: Decomposition of Rhodopsin to Retinene
- This is incorrect. While rhodopsin does break down in light, during dark adaptation, we need to regenerate rhodopsin, not decompose it.

- **Option D**: Decomposition of Rhodopsin to Scotopsin
- This is also incorrect. Similar to option C, the decomposition of rhodopsin would hinder vision in low light, as rods are crucial for seeing in dim conditions.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Option B**: Conversion of Trans-Retinine to 11-Cis-Retinine.