What is the name of the period between nuclear divisions during which the nucleus directs cell activity and replicates chromosomes?

The period between nuclear divisions during which the nucleus directs cell activity and replicates chromosomes is known as interphase. During interphase, the cell is not actively dividing but is engaged in preparatory processes essential for cell division. This phase is critical as it involves three sub-phases: G1 phase (cell growth and normal metabolic roles), S phase (synthesis phase where DNA is replicated), and G2 phase (further growth and preparation for mitosis).

During interphase, chromosomes are not yet distinguishable as separate entities, as they are in a relaxed state called chromatin, allowing for the transcription of DNA and the synthesis of proteins necessary for the cell's functions. This preparation and replication ensure that, when the cell finally does divide, each daughter cell will receive an identical set of chromosomes. In contrast, the other phases listed, such as metaphase, anaphase, and telophase, refer to specific stages within the actual process of mitosis, when the cell is actively dividing rather than preparing for division.