In an experiment in which photosynthesis is perforemd during the day. You provide a plant with radioactive carbon dioxide `(.^(14)CO_(2))` as a metabolic tracer. The `.^(14)C` is incorporated first into oxaloacetic acid. The plant is best characterised as a

Options

A. `C_(4)` plant
B. `C_(3)` plant
C. CAM plant
D. Insectivorous plant.

Explanation

To solve the question regarding the characterization of a plant that incorporates radioactive carbon dioxide \(^{14}CO_2\) into oxaloacetic acid during photosynthesis, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Context**: The question states that photosynthesis is performed during the day, and the plant is provided with radioactive carbon dioxide \(^{14}CO_2\). This indicates that we are looking at a specific metabolic pathway in plants.

**Hint**: Remember that photosynthesis occurs in two main stages: light-dependent reactions and light-independent reactions (Calvin cycle).

2. **Identifying the Product**: The radioactive carbon is incorporated first into oxaloacetic acid. This is a crucial detail because it indicates the type of photosynthetic pathway the plant is using.

**Hint**: Oxaloacetic acid is a four-carbon compound. Think about which photosynthetic pathways produce oxaloacetic acid as a primary product.

3. **Recognizing the Pathway**: The incorporation of carbon into oxaloacetic acid suggests that the plant is utilizing the C4 photosynthetic pathway. In C4 plants, carbon dioxide is first fixed into a four-carbon compound (oxaloacetic acid) before entering the Calvin cycle.

**Hint**: Recall the difference between C3 and C4 plants. C4 plants are adapted to high light intensity and temperatures.

4. **Conclusion**: Based on the information provided, the plant that incorporates \(^{14}CO_2\) into oxaloacetic acid is best characterized as a C4 plant.

**Hint**: C4 plants are often found in tropical and subtropical regions due to their efficiency in photosynthesis under high light and temperature conditions.

### Final Answer:
The plant is best characterized as a **C4 plant**.