In metaphase of mitosis, the chromosomes

Options

A. Break and disintegrate
B. Undergo condensation
C. Line up at equator
D. Decondense and elongate.

Answer

**Step-by-Step Solution:**

1. **Understanding Mitosis**: Mitosis is a type of cell division that results in two daughter cells, each having the same number of chromosomes as the parent cell. It consists of several phases: prophase, metaphase, anaphase, and telophase.

2. **Identifying the Phases**:
- **Prophase**: Chromosomes condense and become visible, spindle fibers begin to form, and the nuclear envelope starts to disappear.
- **Metaphase**: This is the phase in question. During metaphase, chromosomes align at the equatorial plane (also known as the metaphase plate).
- **Anaphase**: Sister chromatids separate and move toward opposite poles of the cell.
- **Telophase**: Chromosomes decondense, and the nuclear envelope re-forms.

3. **Focusing on Metaphase**: In metaphase, the key event is that all chromosomes line up at the equator of the cell. This alignment is crucial for ensuring that each daughter cell will receive an identical set of chromosomes during the subsequent division.

4. **Evaluating the Options**:
- **Break and disintegrate**: This occurs during anaphase, not metaphase.
- **Undergo condensation**: This happens during prophase, not metaphase.
- **Line up at equator**: This is correct; chromosomes align at the metaphase plate during metaphase.
- **Decondense and elongate**: This occurs during telophase, not metaphase.

5. **Conclusion**: The correct answer is that during metaphase of mitosis, the chromosomes line up at the equator.

**Final Answer**: The correct option is **C: line up at equator**.

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