Synthesis of sugars in all photosynthetic plants takes place by

Options

A. `CO_2` fixation with PEP case
B. Calvin cycle reaction
C. Hatch and Slack reactions
D. Both `C_3 and C_4` cycle reactions

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the process through which sugars are synthesized in all photosynthetic plants.

2. **Identifying the Options**: The options provided are:
- A) CO2 fixation with PEP case
- B) Calvin cycle reaction
- C) Hatch and Slack reaction
- D) Both C3 and C4 cycle reactions

3. **Analyzing Each Option**:
- **Option A (CO2 fixation with PEP case)**: This refers to a process primarily associated with C4 plants, where CO2 is fixed using phosphoenolpyruvate carboxylase (PEP case). It is not the primary pathway for sugar synthesis in all photosynthetic plants.
- **Option B (Calvin cycle reaction)**: The Calvin cycle is a series of biochemical reactions that take place in the chloroplasts of photosynthetic organisms. It is the primary pathway for sugar synthesis in all photosynthetic plants, making this a strong candidate.
- **Option C (Hatch and Slack reaction)**: This refers to a variation of the Calvin cycle found in C4 plants, which is not applicable to all photosynthetic plants.
- **Option D (Both C3 and C4 cycle reactions)**: While both cycles are involved in photosynthesis, the question specifically asks for the synthesis of sugars in all photosynthetic plants, which is primarily through the Calvin cycle.

4. **Conclusion**: After analyzing the options, it is clear that the synthesis of sugars in all photosynthetic plants occurs mainly through the Calvin cycle.

5. **Final Answer**: The correct answer is **B) Calvin cycle reaction**.

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