S phase is the DNA synthesis phase. During this portion of the cell cycle, the cell replicates its entire complement of DNA. It also forms the centrosome, which is the microtubule-organizing center that will eventually help the cell pull apart the DNA that will be divided between daughter cells.
1. red blood cells
2. diploid is a type of cell with two sets of chromosomes (usually from the mother and farther)
haploid is a sex cell, so it is a cell with a single set of chromosomes (egg and sperm cells)