Sexual reproduction is oogamous and accompanied by complete post-fertilization developments in the members of:
| 1. | Chlorophyceae |
| 2. | Phaeophyceae |
| 3. | Rhodophyceae |
| 4. | Both Chlorophyceae and Phaeophyceae |
| 1. | Red algae | 2. | Green algae |
| 3. | Brown algae | 4. | Blue green algae |