Mannitol is the stored food in:

Options

A. Fucus
B. Gracilaria
C. Chara
D. Porphyra

Answer

To determine where mannitol is stored as food, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organisms**: The question lists four organisms: Fucus, Gracilaria, Cara, and Porphyra. We need to identify which of these organisms are algae and their respective classes.

2. **Classify the Algae**:
- **Fucus**: This is classified as Brown Algae (Phaeophyceae).
- **Gracilaria**: This is classified as Red Algae (Rhodophyceae).
- **Cara**: This is classified as Green Algae (Chlorophyceae).
- **Porphyra**: This is also classified as Red Algae (Rhodophyceae).

3. **Determine Stored Food**:
- **Brown Algae (Fucus)**: The stored food in Brown Algae is mannitol and laminarin.
- **Red Algae (Gracilaria and Porphyra)**: The stored food in Red Algae is floridean starch.
- **Green Algae (Cara)**: The stored food in Green Algae is starch.

4. **Conclusion**: Since mannitol is specifically mentioned as the stored food in Brown Algae, and Fucus is an example of Brown Algae, the correct answer to the question is Fucus.

### Final Answer:
Mannitol is the stored food in **Fucus**.

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