Which of the following kinds of plant fixes carbon dioxide by way of crassulacean acid metabolism (CAM)

Options

A. Oak tree
B. Cactus
C. Grass
D. Red alga

Answer

To determine which kind of plant fixes carbon dioxide through Crassulacean Acid Metabolism (CAM), we can follow these steps:

### Step-by-Step Solution:

1. **Understand CAM Photosynthesis**:
- CAM is a photosynthetic adaptation found in certain plants, particularly those in arid environments. It allows them to fix carbon dioxide at night, minimizing water loss during the hot daytime.

2. **Identify the Types of Plants**:
- The options given are:
- a) Oak tree
- b) Cactus
- c) Grass
- d) Red alga

3. **Analyze Each Option**:
- **Oak Tree**: This is a deciduous tree that typically uses the C3 photosynthesis pathway, not CAM.
- **Cactus**: Cacti are succulents and are well-known for using CAM to conserve water in dry environments.
- **Grass**: Most grasses use C4 photosynthesis, which is different from CAM.
- **Red Alga**: While some algae can perform photosynthesis, they do not typically use CAM.

4. **Conclusion**:
- The plant that fixes carbon dioxide through CAM is the **Cactus**.

### Final Answer:
The correct answer is **b) Cactus**.

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