Sexual cycle is absent in :-

Options

A. Phycomycetes
B. Deuteromycetes
C. Ascomycetes
D. Basidomycetes

Answer

**Step-by-Step Solution:**

1. **Understanding the Classes of Fungi**: The question asks which class of fungi does not exhibit a sexual cycle. The classes mentioned are phycomycetes, deuteromycetes, ascomycetes, and basidiomycetes.

2. **Analyzing Phycomycetes**: Phycomycetes are known to reproduce both asexually and sexually. They produce zygospores during sexual reproduction. Therefore, they do have a sexual cycle.

3. **Analyzing Deuteromycetes**: Deuteromycetes, also known as imperfect fungi, are unique because sexual reproduction has not been observed in this class. They reproduce asexually through methods like fragmentation and budding. This indicates that the sexual cycle is absent in deuteromycetes.

4. **Analyzing Ascomycetes**: Ascomycetes reproduce both sexually and asexually. During sexual reproduction, they produce ascospores, which are contained in special structures called asci. Hence, they do have a sexual cycle.

5. **Analyzing Basidiomycetes**: Basidiomycetes also reproduce both asexually and sexually. They produce basidiospores during sexual reproduction, indicating the presence of a sexual cycle.

6. **Conclusion**: Based on the analysis, the class of fungi that does not exhibit a sexual cycle is **Deuteromycetes**.

**Final Answer**: Sexual cycle is absent in **Deuteromycetes**.

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