BOTANY

Detailed explanation-1: -Centrioles duplicate during the S phase of the cell cycle and it results in the formation of four centrioles prior to cell division. They help in distributing the duplicated genetic material equally. Also, during S phase, DNA replication occurs inside the nucleus.

Detailed explanation-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).

Detailed explanation-3: -M phase. During the mitotic (M) phase, the cell divides its copied DNA and cytoplasm to make two new cells. M phase involves two distinct division-related processes: mitosis and cytokinesis.

Detailed explanation-4: -So, the correct option is ‘ S phase’.

Detailed explanation-5: -In most somatic cells, centriole duplication occurs during S phase and is marked by the formation of procentrioles at the proximal end of each parental centriole.