A process that makes important difference between `C_(3)` and `C_(4)` plants is
(a) Glycolysis
(b) Photosynthesis
(c) Photorespiration
(d) Transpiration

Options

A. Glycolysis
B. Photosynthesis
C. Photorespiration
D. Transpiration

Answer

To solve the question regarding the process that makes an important difference between C3 and C4 plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understand C3 and C4 Plants**:
- C3 plants primarily use the Calvin cycle for carbon fixation, which occurs in the mesophyll cells.
- C4 plants have a specialized mechanism that involves the fixation of carbon dioxide in mesophyll cells and then transferring it to bundle sheath cells where the Calvin cycle occurs.

2. **Identify the Key Processes**:
- The main processes involved in photosynthesis include light reactions and dark reactions (Calvin cycle).
- Photorespiration is a process that can occur in C3 plants when the enzyme RuBisCO reacts with oxygen instead of carbon dioxide.

3. **Analyze the Options**:
- **(a) Glycolysis**: This is a metabolic pathway that breaks down glucose for energy, not directly related to the differences between C3 and C4 plants.
- **(b) Photosynthesis**: Both C3 and C4 plants perform photosynthesis, but they do so differently.
- **(c) Photorespiration**: This is a significant process that occurs in C3 plants but is minimized in C4 plants due to their unique anatomy and carbon fixation pathway.
- **(d) Transpiration**: This is the process of water movement through a plant and its evaporation from aerial parts, not a distinguishing factor between C3 and C4 plants.

4. **Conclusion**:
- The most significant difference between C3 and C4 plants lies in the occurrence of photorespiration. C3 plants are more prone to photorespiration due to the presence of RuBisCO in mesophyll cells, whereas C4 plants have adapted to minimize this process through their specialized anatomy.
- Therefore, the correct answer is **(c) Photorespiration**.