`C_4` plants among the following are

Options

A. Maize
B. Sugarcane
C. Opuntia
D. 1 & 2

Answer

To determine which of the given options are C4 plants, we can follow these steps:

### Step 1: Understand C4 Plants
C4 plants are a group of plants that have a specific photosynthetic pathway that allows them to efficiently fix carbon dioxide in conditions of high light intensity, high temperatures, and low carbon dioxide concentrations. This pathway is advantageous in hot and dry environments.

### Step 2: Analyze the Options
We have the following options to consider:
1. Maize
2. Sugarcane
3. Opuntia
4. Option 1 and 2 (both maize and sugarcane)

### Step 3: Identify C4 Plants
- **Maize (Zea mays)**: This is a well-known C4 plant that thrives in warm climates and is efficient in photosynthesis under high light conditions.
- **Sugarcane (Saccharum officinarum)**: Another prominent C4 plant, sugarcane is also adapted to hot environments and is known for its high sugar content.
- **Opuntia (Cactus)**: Opuntia follows the CAM (Crassulacean Acid Metabolism) pathway, which is different from the C4 pathway. CAM plants are adapted to arid conditions and typically open their stomata at night to minimize water loss.

### Step 4: Conclusion
Based on the analysis:
- Maize and sugarcane are both C4 plants.
- Opuntia is not a C4 plant; it uses the CAM pathway.

Thus, the correct answer is option 4, which includes both maize and sugarcane.

### Final Answer
**C4 plants among the following are: Option 4 (1 and 2 - both maize and sugarcane).**

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