Question

shown at right is a diagram of a cell in the second phase of mitosis, metaphase. what has happened in metaphase? select all that apply: chromosomes are lining up in the middle of the cell chromosomes have multiplied the chromosomes have connected to something on either end of the cell the nucleus has dissolved the cell has divided

Explanation:

1. Chromosomes are lining up in the middle of the cell: In metaphase of mitosis, chromosomes align at the cell's equatorial plane (middle). This is a key characteristic of metaphase.
2. The chromosomes have connected to something on either end of the cell: Chromosomes attach to spindle fibers (from centrosomes at cell poles) during metaphase, which helps in their alignment and subsequent separation.
3. The nucleus has dissolved: During prophase (the first phase of mitosis), the nuclear envelope breaks down (the nucleus "dissolves"). By metaphase, this has already occurred, so this is true for the cell in metaphase (since metaphase follows prophase).
4. Chromosomes have multiplied: Chromosome replication (multiplication) occurs during the S - phase of interphase, not during metaphase. So this is incorrect.
5. The cell has divided: Cell division (cytokinesis) occurs after mitosis (telophase and cytokinesis). During metaphase, the cell has not yet divided. So this is incorrect.

Answer:

• Chromosomes are lining up in the middle of the cell
• The chromosomes have connected to something on either end of the cell
• The nucleus has dissolved