Which one of the following shows isogamy with non­flagellated gametes?

Explanation

A. Sargassum: Sargassum is a brown alga that reproduces sexually. However, it does not exhibit isogamy with non-flagellated gametes. Instead, it displays oogamy, where large non-motile eggs are fertilized by small motile sperm. B.Ectocarpus: Ectocarpus is a brown alga that also reproduces sexually. It does not demonstrate isogamy with non-flagellated gametes either. Ectocarpus exhibits oogamy, where two morphologically distinct types of gametes are produced: larger non-motile eggs and smaller motile sperm C. Ulothrix: Ulothrix is a filamentous green alga that undergoes both sexual and asexual reproduction. In sexual reproduction, Ulothrix exhibits isogamy, where gametes of similar size and structure (isogametes) are produced. However, the gametes in Ulothrix are flagellated, so it does not match the condition of non-flagellated gametes. D.Sexual reproduction in algae takes place through the fusion of two gametes. In Spirogyra, the gametes are similar in size (isogamy) and non­ flagellated (non­motile).