Explanation

The S and $G_{2}$-phases of interphase are followed by prophase. Prophase is marked by the initiation of condensation of chromosomal material. The chromosomal material become untangled during the process of chromatin condensation. Centriole, now begins to move towards opposite poles of the cell. Therefore, when dividing cells are examined under a light microscope, in prophase only the chromosomes become visible