Male gametes are flagellated in

Option a: Ectocarpus

Ectocarpus is a type of brown algae that is known for its motile male gametes. The male gametes are equipped with flagella that allow them to swim through water to reach the female gametes. Therefore, in Ectocarpus, the male gametes are flagellated.

Option b: Spirogyra

Spirogyra is a type of green algae, but it does not produce motile, flagellated male gametes. Instead, it reproduces through a process called conjugation, where cells align and transfer genetic material directly. Since the male gametes are not flagellated in Spirogyra, this option is incorrect.

Option c: Polysiphonia

Polysiphonia is a red algae, and like many other red algae, its male gametes lack flagella. The gametes are non-motile and depend on water currents for movement. This means the male gametes are not flagellated in Polysiphonia.

Option d: Anabaena

Anabaena is a genus of cyanobacteria. It reproduces asexually and does not form male gametes with flagella. Since male gametes are not flagellated in Anabaena, this option is also incorrect.

Correct Answer: a) Ectocarpus

Explanation:

Among the given options, Ectocarpus is the only organism where male gametes are flagellated. These gametes use their flagella to move in water and locate the female gametes for fertilization. This trait is not seen in the other listed organisms—Spirogyra uses conjugation without flagella, Polysiphonia has non-motile gametes, and Anabaena reproduces asexually without forming flagellated male gametes.