Dark reaction in photosynthesis is called so because

Options

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

Explanation

### Step-by-Step Solution:

1. **Understanding the Term "Dark Reaction":**
- The term "dark reaction" refers to a set of biochemical processes in photosynthesis that do not require light directly to occur. This is why it is called a "dark" reaction.

2. **Light Independence:**
- Dark reactions are often referred to as "light-independent reactions" because they do not directly utilize light energy. Instead, they can occur in the absence of light.

3. **Dependence on Light Reactions:**
- Although dark reactions do not require light, they are indirectly dependent on the light reactions. The light reactions capture light energy and produce energy-rich molecules (like ATP and NADPH) that are used in the dark reactions.

4. **Products of Light Reactions:**
- The products of the light reactions (ATP and NADPH) are essential for driving the dark reactions. Therefore, while dark reactions do not need light to occur, they rely on the end products of the light reactions.

5. **Absence of Photosystems:**
- In dark reactions, there are no photosystems involved, and photolysis of water (which occurs in light reactions) is not required.

6. **Conclusion:**
- The dark reaction is called so because it does not directly depend on light energy, but it is essential for the overall process of photosynthesis, relying on the products generated by the light reactions.