The interface between the G1 and S phases is called the Restriction point. The restriction point is a checkpoint in the cell cycle that determines whether a cell will proceed into the S phase (DNA synthesis phase) or exit the cell cycle and enter the G0 phase (a resting phase). This point is a critical control mechanism in the regulation of the cell cycle, particularly in response to environmental signals such as growth factors and nutrients.
Consider the following statements:
(A) Availability is generally conserved.
(B) Availability can neither be negative nor positive.
(C) Availability is the maximum theoretical work obtainable.
(D) Availability can be destroyed in irreversibility's.