Question

in which phase single stranded chromosome is formed​

Answer 1

A daughter chromosome is a chromosome that results from the separation of sister chromatids during cell division. Daughter chromosomes originate from a single stranded chromosome that replicates during the synthesis phase (S phase) of the cell cycle

Answer 2

In the eukaryotic cell cycle, chromosome duplication occurs during "S phase" (the phase of DNA synthesis) and chromosome segregation occurs during "M phase" (the mitosis phase).