Which one of the following statements that contrasts mitosis and meiosis is correct ?

Options

A. Cell divided by cytokinesis only in mitosis
B. DNA is replicated before the start of meiosis only
C. Spindles consisting of microtubule form only in mitosis
D. Exchange of genetic materials occurs only in meiosis

Answer

To determine which statement correctly contrasts mitosis and meiosis, we need to analyze the provided options one by one.

### Step-by-Step Solution:

1. **Understand Mitosis and Meiosis**:
- Mitosis is a type of cell division that results in two genetically identical daughter cells, while meiosis is a specialized form of cell division that reduces the chromosome number by half, leading to the formation of gametes (sperm and eggs).

2. **Evaluate the Options**:
- **Option 1**: "Cell divided by Cytokinesis only in the mitosis."
- This statement is incorrect because cytokinesis occurs in both mitosis and meiosis.

- **Option 2**: "Cytokinesis is a concern of Cytoplasm division. Cytoplasm division is also present in mitosis and meiosis."
- This statement is true, but it does not contrast the two processes effectively.

- **Option 3**: "DNA is replicated before the starting of meiosis only."
- This statement is incorrect because DNA replication occurs before both mitosis and meiosis during the S phase of interphase.

- **Option 4**: "Exchange of the genetic material occurs only in meiosis."
- This statement is correct. During meiosis, specifically in prophase I, homologous chromosomes undergo a process called crossing over, which leads to the exchange of genetic material. This does not occur in mitosis.

3. **Conclusion**:
- The correct contrasting statement between mitosis and meiosis is **Option 4**: "Exchange of the genetic material occurs only in meiosis."

### Final Answer:
The correct statement that contrasts mitosis and meiosis is **Option 4: Exchange of the genetic material occurs only in meiosis.**

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