The common feature in `CAM` and `C_(4)` plants is

Options

A. Stomata open only during night
B. Acid concentration increases during night
C. Both `C_(3)` and `C_(4)` pathways occur
D. Having kranz anatomy.

Answer

To determine the common feature in CAM (Crassulacean Acid Metabolism) and C4 plants, we need to analyze the characteristics of both types of plants and their photosynthetic processes.

### Step-by-Step Solution:

1. **Understanding CAM and C4 Plants**:
- CAM plants, such as succulents, open their stomata at night to minimize water loss and store carbon dioxide as malate.
- C4 plants, like maize and sugarcane, have a different mechanism where they fix carbon dioxide during the day using a four-carbon compound.

2. **Analyzing the Options**:
- **Option 1**: "Stomata open only during night."
- This is true for CAM plants but not for C4 plants, which can have stomata open during the day. Thus, this is not a common feature.

- **Option 2**: "Acid concentration increases during night."
- This is true for CAM plants where malic acid accumulates at night, but in C4 plants, acid concentration does not increase at night. Hence, this is also not a common feature.

- **Option 3**: "Both C3 and C4 pathways occur."
- This is correct. In CAM and C4 plants, the C4 pathway is utilized for carbon fixation, and subsequently, the C3 pathway (Calvin cycle) occurs for sugar production. This is indeed a common feature.

- **Option 4**: "They both have Kranz anatomy."
- Kranz anatomy is a characteristic of C4 plants, where the vascular bundles are surrounded by a layer of bundle sheath cells. CAM plants do not exhibit this structure, making this option incorrect.

3. **Conclusion**:
- The common feature in CAM and C4 plants is that both utilize the C4 pathway followed by the C3 pathway for photosynthesis.

### Final Answer:
The common feature in CAM and C4 plants is that both C3 and C4 pathways occur.