The S phase stands for synthesis, which means to make or build something more complex out of simpler parts. Scientists know that during the S phase DNA is being made in the nucleus of the cell. Why do you think the cells needs to make more DNA at this time in the cell cycle?
a. The chromosomes must be on opposite sides of the cell before the cells divide.
b. The DNA needs to be copied so each cell has a complete set of DNA.
c. The cells would have only half the original amount of DNA needed.
d. Chromosomes make sure DNA is separated evenly during cell division.
