`C_(4)` and `C_(3)` pathways of `CAM` plants are separated by

Options

A. Bundle sheath
B. Mesophyll and bundle sheath cells
C. Mesophyll and bundle sheath chloroplasts
D. Time.

Answer

To answer the question about what separates the C4 and C3 pathways in CAM plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understand CAM Plants**: CAM stands for Crassulacean Acid Metabolism. These plants have adapted to arid conditions by modifying their photosynthetic processes.

2. **Identify the Photosynthetic Pathways**: CAM plants utilize both C4 and C3 pathways for photosynthesis. The C4 pathway involves the initial fixation of carbon dioxide into a four-carbon compound, while the C3 pathway involves the fixation of carbon dioxide into a three-carbon compound.

3. **Timing of Processes**: In CAM plants, the stomata (the pores for gas exchange) are closed during the day to minimize water loss and open at night to take in carbon dioxide. This is a crucial adaptation for survival in dry environments.

4. **C4 Pathway at Night**: During the night, when the stomata are open, carbon dioxide is fixed into a four-carbon compound (oxaloacetate) and then converted into malic acid. This process occurs in the dark.

5. **C3 Pathway During the Day**: During the day, the malic acid is converted back into pyruvic acid, releasing carbon dioxide. This released carbon dioxide is then fixed by ribulose bisphosphate (RuBP) in the C3 pathway.

6. **Conclusion**: The C4 and C3 pathways in CAM plants are separated by time; the C4 pathway occurs at night, while the C3 pathway occurs during the day.

### Final Answer:
The C4 and C3 pathways of CAM plants are separated by time.

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