A dikaryon is formed when

Options

A. meiosis is arrested
B. the two haploid cells do not fuse imme- diately
C. cytoplasm does not fuse
D. none of the above

Answer

To answer the question "A dikaryon is formed when", let's break it down step by step:

### Step 1: Understand the term "dikaryon"
A dikaryon refers to a specific condition in fungi where two haploid nuclei coexist in the same cell without fusing. This means that there are two distinct nuclei present, each derived from different haploid cells.

### Step 2: Analyze the options
We have four options to consider:
- **A. Meiosis is arrested**: This option suggests that the process of meiosis is halted, but this does not directly relate to the formation of a dikaryon.
- **B. The two haploid cells do not fuse immediately**: This option indicates that the two haploid cells remain separate and do not combine their nuclei right away, which is a key characteristic of dikaryon formation.
- **C. Cytoplasm does not fuse**: While this might seem relevant, the definition of a dikaryon focuses more on the nuclei rather than the cytoplasm.
- **D. None of the above**: This option suggests that none of the previous statements are correct.

### Step 3: Determine the correct answer
Given that a dikaryon is specifically characterized by the presence of two haploid nuclei that do not fuse immediately, the best choice is **B. The two haploid cells do not fuse immediately**. This option aligns perfectly with the definition of a dikaryon.

### Conclusion
Thus, the correct answer to the question is **B**.

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