Question

during which phase of mitosis do the nuclear envelope and nucleoli disappear?
○ metaphase
○ anaphase
○ telophase
○ prophase

Explanation:

To solve this, we analyze each mitosis phase:

• Metaphase: Chromosomes align at the equator; nuclear envelope/nucleoli already gone.
• Anaphase: Sister chromatids separate; nuclear structures gone earlier.
• Telophase: Nuclear envelope reforms, nucleoli reappear.
• Prophase: Chromatin condenses, spindle forms, and nuclear envelope + nucleoli disappear.

So the phase where nuclear envelope and nucleoli disappear is Prophase.

Answer:

D. Prophase