Explain the four steps of interphase?

The four main stages of Interphase are Gap 0, Gap 1, S phase and Gap 2. Interphase appears to be a resting stage in cell divisions but actually many activities or processes happens at this phase. Interphase generally lasts at least 12 to 24 hours in mammalian tissue.

First it is Gap 0
then Gap 1
Gap2
and finally S