Dark reaction in photosynthesis is called so because

Options

A. it can occur in dark also
B. it does not depend on light energy
C. it cannot occur during day light
D. it occurs more rapidly at night

Answer

### Step-by-Step Solution:

1. **Understanding the Dark Reaction**: The dark reaction in photosynthesis is also known as the Calvin cycle. It is the second stage of photosynthesis that does not directly require light to occur.

2. **Location of Dark Reaction**: The dark reaction takes place in the stroma of chloroplasts, where the ATP and NADPH produced in the light reaction are used to convert carbon dioxide into glucose.

3. **Reason for the Name**: The term "dark reaction" is somewhat misleading. It is called so because it does not require light directly. However, it can occur in the presence of light as well.

4. **Analyzing the Options**:
- **Option A**: "It can occur in dark also" - This is true, but it can also occur in light, making it a misleading statement.
- **Option B**: "It does not depend on light energy" - This is correct. The dark reaction does not require light directly.
- **Option C**: "It cannot occur during daylight" - This is incorrect; the dark reaction can occur during the day.
- **Option D**: "It occurs more rapidly at night" - This is also incorrect; the rate of the dark reaction can vary based on plant type and environmental conditions, not strictly limited to night.

5. **Conclusion**: The best answer to the question is that the dark reaction is called so because it does not depend on light energy (Option B).