In which of the following, belongs to the same class of algae?

Options

A. Chara, Fucus, Polysiphonia
B. Volvox, Spirogyra, Chlamydomonas
C. Porphyra, Ectocarpus, Ulothrix
D. Sargassum, Laminaria, Gracillaria

Answer

To determine which of the given options contains algae that belong to the same class, we will analyze each option step by step.

### Step 1: Analyze the first option - Chara, Fucus, and Polysiphonia
- **Chara**: This is classified as **Chlorophyceae**, which is the class of green algae.
- **Fucus**: This belongs to **Phaeophyceae**, which is the class of brown algae.
- **Polysiphonia**: This is classified as **Rhodophyceae**, which is the class of red algae.

**Conclusion for Option 1**: Since Chara, Fucus, and Polysiphonia belong to different classes (green, brown, and red algae respectively), this option is incorrect.

### Step 2: Analyze the second option - Volvox, Spirogyra, and Clamydomonas
- **Volvox**: This is classified under **Chlorophyceae** (green algae).
- **Spirogyra**: This also belongs to **Chlorophyceae** (green algae).
- **Clamydomonas**: This is also classified as **Chlorophyceae** (green algae).

**Conclusion for Option 2**: All three (Volvox, Spirogyra, and Clamydomonas) belong to the same class, which is **Chlorophyceae**. Therefore, this option is correct.

### Step 3: Analyze the third option - Porphyra, Ectocarpus, and Eleuthyx
- **Porphyra**: This belongs to **Rhodophyceae** (red algae).
- **Ectocarpus**: This is classified under **Phaeophyceae** (brown algae).
- **Eleuthyx**: This is also classified under **Phaeophyceae** (brown algae).

**Conclusion for Option 3**: Since Porphyra is a red algae and Ectocarpus and Eleuthyx are both brown algae, this option is incorrect as they do not belong to the same class.

### Step 4: Analyze the fourth option - Sargassum, Laminaria, and Gracilaria
- **Sargassum**: This belongs to **Phaeophyceae** (brown algae).
- **Laminaria**: This is also classified under **Phaeophyceae** (brown algae).
- **Gracilaria**: This belongs to **Rhodophyceae** (red algae).

**Conclusion for Option 4**: Since Sargassum and Laminaria are both brown algae, but Gracilaria is a red algae, this option is also incorrect.

### Final Conclusion
The only option where all the algae belong to the same class is **Option 2: Volvox, Spirogyra, and Clamydomonas**, which are all classified under **Chlorophyceae**.