What is the order of the cell cycle

The cell cycle  is a four-stage process in which the cell increases in size (gap 1, or G1, stage), copies its DNA (synthesis, or S, stage), prepares to divide (gap 2, or G2, stage), and divides (mitosis, or M, stage). The stages G1, S, and G2 make up interphase, which accounts for the span between cell divisions.

your answer is "the 1950's"

the sphincter muscles at the end of the digestive tract is the anus.