Question

during this phase chromosomes are aligned on the equatorial plane, midway between the two poles of the cell. the sister chromatids are still tightly attached to each other. at this time, the chromosomes are maximally condensed. telophase metaphase anaphase prophase

Explanation:

To solve this, we analyze each phase of mitosis:

• Telophase: Involves chromosome decondensation and nuclear envelope reformation, not alignment on the equatorial plane. Eliminate this.
• Metaphase: Chromosomes align at the cell's equatorial plane (metaphase plate), sister chromatids are attached, and chromosomes are maximally condensed. This matches the description.
• Anaphase: Sister chromatids separate and move to opposite poles, so they are not attached. Eliminate this.
• Prophase: Chromosomes condense and the spindle forms, but alignment at the equator hasn't occurred yet. Eliminate this.

Answer:

B. metaphase