Question

what happens in the nuclei of cells before a cell can start dividing via mitosis?
dna replication
cytoplasm separation
cell membrane regeneration
crossing over o chromosomes

Explanation:

Mitosis produces two genetically identical daughter cells, so the cell must first duplicate its genetic material in the nucleus. DNA replication occurs during the S phase of interphase, before mitosis begins. Cytoplasm separation happens during cytokinesis (after mitosis), cell membrane regeneration is not a pre-mitotic nuclear event, and crossing over occurs in meiosis, not mitosis.

Answer:

DNA replication