When chromosomes are duplicated before cells divide, in a process called?

The process is called Mitosis

Explanation: Mitosis is the process in which a eukaryotic cell (cell containing a nucleus) separates its already duplicated chromosomes (copied during the S phase) into two sets of chromosomes so there will be two identical nuclei. It is generally followed by cytokinesis which divides the cytoplasm and cell membrane.

Hope this helps:)

geologic time scale (for gradpoint) =)