A. what are the four major stages of the cell cycle? b. which stages are included in interphase? c. what events distinguish g1 s, and g2?

The 4 major stages of the cell cycle are M phase, G1 phase,S phase, and G2 phase.

The stages includes interphase are G1 phase, S phase, and G2 phase.  

Explanation:

The cell cycle is a 4 stage process that leads to cell division. In eukaryotic cells, genome replication is coordinated with the cell cycle. Hence 2 copies of the entire genome are available when the cell divides.  

The dividing cells undergo repeated cycles of metaphase, when nuclear and cell division occurs and the interphase where DNA replication occurs combined known as the cell cycle. The 4 stages of the cell cycle are M-phase (mitosis), G1 Phase (gap 1), S-phase (synthesis phase), and G2 phase (gap 2).

The interphase is also known as the resting phase. But it is a preparatory phase for cell division. During this phase, histone proteins are formed and centrioles divide to form 2 new centrioles.

Interphase has 3 phases of the cell cycle except for M-phase. These are the G1 phase, S phase, and G2 phase.

G- phase: It is the postmitotic gap phase. It occurs at the end of the mitotic cell division. RNA and proteins are synthesized in this phase but not the DNA.  

S-phase: During this phase, DNA is synthesized. In this period DNA content of the nucleus is doubled.  

G2 - phase: This is the premitotic gap phase. Here synthesis of RNA and protein continues. The DNA synthesis stops in this phase.

M-Phase: It is the mitosis period when the nucleus and cell divide.

All human cell division takes 20 hrs to complete. G1 phase takes 9 hrs, and S-phase takes 8 hrs to complete. G2 phase completes in 2 hrs and the M phase takes only 45 min. The G1 and S phase is the longest phase in the cell division.