`C_(4)` Plants differ from `C_(3)` plants with respect to
(a) First product
(b) Substrate which accepts carbon dioxide
(c) Number of A T P molecules consumed
(d) All the above

Options

A. First product
B. Substrate which accepts carbon dioxide
C. Number of `ATP` molecules consumed
D. All the above.

Answer

To solve the question regarding the differences between C4 and C3 plants, we will analyze each option provided:

### Step-by-Step Solution:

1. **First Product**:
- In C3 plants, the first product of carbon fixation is **3-phosphoglycerate (3-PGA)**, which is a three-carbon compound.
- In C4 plants, the first product formed is **oxaloacetate (OAA)**, which is a four-carbon compound.
- **Conclusion**: The first product differs between C3 and C4 plants.

2. **Substrate that Accepts Carbon Dioxide**:
- In C3 plants, the substrate that accepts carbon dioxide is **ribulose bisphosphate (RuBP)**.
- In C4 plants, the substrate that accepts carbon dioxide is **phosphoenolpyruvate (PEP)**.
- **Conclusion**: The substrate that accepts carbon dioxide also differs between C3 and C4 plants.

3. **Number of ATP Molecules Consumed**:
- C3 plants use approximately **18 ATP molecules** to fix six molecules of carbon dioxide.
- C4 plants consume about **30 ATP molecules** to fix the same amount of carbon dioxide.
- **Conclusion**: The number of ATP molecules consumed differs between C3 and C4 plants.

4. **Final Conclusion**:
- Since all three aspects (first product, substrate for carbon fixation, and number of ATP molecules consumed) differ between C3 and C4 plants, the correct answer is **(d) All the above**.

### Final Answer:
**(d) All the above**

---