After karyogamy followed by meiosis, spores are produced exogenously in

Options

A. Neurospora
B. Alternaria
C. Agaricus
D. Saccharomyces

Answer

To solve the question, "After karyogamy followed by meiosis, spores are produced exogenously in which of the following: Neurospora, Alternaria, Agaricus, or Saccharomyces?", we will analyze each option step by step.

### Step 1: Understand the terms
- **Karyogamy**: This is the fusion of two nuclei.
- **Meiosis**: This is a type of cell division that reduces the chromosome number by half, producing spores.
- **Exogenous**: This means that the spores are produced outside the fruiting body.

### Step 2: Analyze each option

1. **Neurospora**:
- Neurospora belongs to the Ascomycetes group (sac fungi).
- The spores produced are called ascospores.
- Ascospores are formed inside a structure called ascocarp.
- Therefore, Neurospora produces spores **endogenously** (inside the sac).

2. **Alternaria**:
- Alternaria is classified as a Deuteromycete (imperfect fungi).
- It does not have a sexual phase and only reproduces asexually.
- Since it does not produce spores through karyogamy and meiosis, it cannot be the correct answer.

3. **Agaricus**:
- Agaricus is a member of the Basidiomycetes group (mushrooms).
- The spores produced are called basidiospores.
- Basidiospores are formed outside the fruiting body known as basidiocarp.
- Therefore, Agaricus produces spores **exogenously** (outside the fruiting body).

4. **Saccharomyces**:
- Saccharomyces is a unicellular yeast and also belongs to the Ascomycetes group.
- The spores produced are ascospores.
- Similar to Neurospora, ascospores are formed inside the ascocarp.
- Thus, Saccharomyces produces spores **endogenously** (inside the fruiting body).

### Step 3: Conclusion
Based on the analysis, the only organism that produces spores exogenously after karyogamy followed by meiosis is **Agaricus**.

### Final Answer:
**Agaricus**

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