In Phaeophyceae, the gametes are

Options

A. pyriform and bear 2 flagella (one longitudinal and another transverse)
B. pear-shaped and bear 2 flagella that are laterally attached
C. pyriform and bear 2-8, equal and apical flagella
D. pear-shaped and bear 2-8, equal and apical flagella

Answer

**Step-by-Step Solution:**

1. **Identify the Group**: The question is about Phaeophyceae, which are commonly known as brown algae.

2. **Understand Gametes**: We need to determine the characteristics of the gametes produced by Phaeophyceae. Gametes are the reproductive cells involved in sexual reproduction.

3. **Types of Gametes**: In Phaeophyceae, gametes can be classified based on their shape and flagella:
- They can be isogamous (similar in size and shape), anisogamous (different in size), or oogamous (large non-motile egg and small motile sperm).
- The gametes are typically biflagellate, meaning they have two flagella.

4. **Shape of Gametes**: The shapes mentioned in the options are pear-shaped and pyreiform.
- The gametes in Phaeophyceae are generally described as pear-shaped.

5. **Flagella Arrangement**: The arrangement of the flagella is also important:
- In Phaeophyceae, the flagella are laterally attached, which means they are positioned on the sides of the gametes.

6. **Evaluate Options**: Based on the characteristics of the gametes:
- Option 1: Pyriform shape with two flagella in different directions (incorrect).
- Option 2: Two flagella attached laterally (correct).
- Option 3: Pyriform shape with 2 to 8 equal flagella at the apex (incorrect).
- Option 4: Pear shape with 2 to 8 equal flagella at the apex (incorrect).

7. **Conclusion**: The correct answer is Option 2, which states that the gametes in Phaeophyceae are pear-shaped with two flagella attached laterally.

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