In which class of algae sexual reproduction is is oogamous and accomapanied by complex post fertilization developments?

Answer

To answer the question regarding which class of algae exhibits oogamous sexual reproduction accompanied by complex post-fertilization developments, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Oogamy**:
- Oogamy is a form of sexual reproduction where there are two types of gametes: a smaller, motile male gamete and a larger, non-motile female gamete.

2. **Identify Algal Classes**:
- Algae are classified into different groups, including green algae (Chlorophyceae), brown algae (Phaeophyceae), and red algae (Rhodophyceae).

3. **Focus on Sexual Reproduction**:
- In the context of algae, we need to determine which class exhibits the oogamous condition.

4. **Recognize the Class with Oogamous Reproduction**:
- The class of algae that is known for having oogamous reproduction is the Red Algae, or Rhodophyceae.

5. **Examples of Red Algae**:
- Some examples of red algae include Porphyra, Gracilaria, Gelidium, and Polysiphonia. These algae not only exhibit oogamous reproduction but also have complex post-fertilization developments.

6. **Conclusion**:
- Therefore, the answer to the question is that the class of algae in which sexual reproduction is oogamous and accompanied by complex post-fertilization developments is **Red Algae (Rhodophyceae)**.

### Final Answer:
**Red Algae (Rhodophyceae)**