Which of the following are not a group of brown algae ?

Options

A. Sargassum and Fucus
B. Ectocarpus, Dictyota
C. Dictyota, Laminaria
D. Sargassum and chara

Answer

To solve the question "Which of the following are not a group of brown algae?", we can follow these steps:

### Step 1: Understand the Classification of Algae
Algae are classified into three main groups based on their pigments and stored food:
- **Chlorophyceae**: Green algae
- **Rhodophyceae**: Red algae
- **Pheophyceae**: Brown algae

### Step 2: Identify the Characteristics of Brown Algae
Brown algae (Pheophyceae) have specific characteristics:
- They contain the pigment **Fucoxanthin**, which gives them their brown color.
- Their stored food includes **mannitol** and **laminarin**.
- Their cell walls are made of **cellulose** and **algin**.
- They contain chlorophyll pigments A and C.

### Step 3: List the Given Options
The options provided in the question are:
1. Sargassum and Fucus
2. Ectocarpus and Dictyota
3. Dictyota and Laminaria
4. Sargassum and Cara

### Step 4: Analyze Each Option
- **Option 1: Sargassum and Fucus** - Both are examples of brown algae.
- **Option 2: Ectocarpus and Dictyota** - Both are also examples of brown algae.
- **Option 3: Dictyota and Laminaria** - Both are examples of brown algae.
- **Option 4: Sargassum and Cara** - Sargassum is a brown algae, but **Cara** (likely referring to Chara) is a green algae.

### Step 5: Conclusion
The only option that includes an organism that is not a brown algae is **Option 4: Sargassum and Cara**. Therefore, the correct answer is that **Cara** is not a group of brown algae.

### Final Answer
**Option 4: Sargassum and Cara** is not a group of brown algae.

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