DNA replication takes place during the S phase of interphase, which is the period before a cell enters mitosis.

Here's why:

* Mitosis is the process of cell division where one cell divides into two identical daughter cells.

* DNA replication is the process of copying the entire genome to ensure that each daughter cell receives a complete set of chromosomes.

Therefore, DNA replication needs to happen before mitosis so that each daughter cell has a full set of genetic material to function.