Q. Maize, sugarcane and some other tropical plants have high efficiency of `CO_(2)` fixation because they operate

Options

A. a) Calvin cycle
B. b) Hatch-Slack cycle
C. c) TCA cycle
D. d) PP pathway.

Answer

To solve the question about why maize, sugarcane, and some other tropical plants have high efficiency of CO2 fixation, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Plants**: Recognize that maize and sugarcane are examples of tropical plants known for their efficient CO2 fixation.

2. **Understand CO2 Fixation Pathways**: There are two main pathways for CO2 fixation in plants: the C3 pathway and the C4 pathway.

3. **Differentiate Between C3 and C4 Pathways**:
- In the **C3 pathway**, the first stable product formed is a 3-carbon molecule (3-phosphoglycerate).
- In the **C4 pathway**, the first stable product is a 4-carbon molecule (oxaloacetic acid).

4. **Identify the First CO2 Acceptor**: In the C4 pathway, the first acceptor of CO2 is phosphoenolpyruvate (PEP), which combines with CO2 to form oxaloacetic acid (OAA).

5. **Name the C4 Pathway**: The C4 pathway is also known as the Hatch and Slack pathway, named after the scientists who discovered it.

6. **Select the Correct Option**: Based on the above information, the correct answer to the question is Option B: HN Slack pathway (Hatch and Slack pathway).

### Final Answer:
Maize, sugarcane, and some other tropical plants have high efficiency of CO2 fixation because they operate through the Hatch and Slack pathway (C4 pathway).

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