In which of the following ways are mitosis and meiosis similar?

Options

A. Both are preceeded by DNA replication
B. Both occur in all kinds of cells
C. Both include the crossing over of chromosomes
D. ( 1) and (3)

Answer

To determine the similarities between mitosis and meiosis, we can analyze the characteristics of both processes step by step.

### Step-by-Step Solution:

1. **Understanding Mitosis and Meiosis**:
- Mitosis is a type of cell division that results in two genetically identical daughter cells and occurs in somatic cells (body cells).
- Meiosis is a specialized type of cell division that results in four genetically diverse daughter cells and occurs in germ cells (reproductive cells).

2. **DNA Replication**:
- Both mitosis and meiosis are preceded by DNA replication during the S phase of the cell cycle. This means that before either process begins, the cell duplicates its DNA to ensure that each daughter cell receives a complete set of chromosomes.

3. **Cell Types**:
- Mitosis occurs in somatic cells, while meiosis occurs in germ cells. Therefore, they do not occur in all types of cells, which means they differ in this aspect.

4. **Crossing Over**:
- Crossing over, which is the exchange of genetic material between homologous chromosomes, occurs during meiosis but not during mitosis. This is a key difference between the two processes.

5. **Conclusion**:
- The only similarity between mitosis and meiosis is that both processes are preceded by DNA replication.

### Final Answer:
The correct similarity between mitosis and meiosis is that **both are preceded by DNA replication**.

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