The __________ checkpoint is also known as restriction point

The correct option is G1 checkpoint.

In the eukaryotic cell cycle, the progression of a cell through various phases (G1, S, G2, and M) is tightly regulated by control mechanisms known as checkpoints. These checkpoints monitor whether the cell is ready to proceed to the next phase.

The checkpoint near the end of the G1 (Growth 1) phase is particularly critical. In animal cells, this G1 checkpoint is widely referred to as the restriction point (often abbreviated as the R point). Once a cell passes this point, it becomes irreversibly committed to entering the S phase (Synthesis phase) and completing the rest of the cell cycle, regardless of external growth factors or signals. If conditions are not favorable (for example, if there is DNA damage or lack of nutrients), the cell will not pass the G1 checkpoint and will instead enter a resting state known as the G0 phase.