The cure (vaccines) to problems like smallpox take a while to develop as scientists and doctors need to make it correctly and test it correctly to see if it is a cure or not. It takes years before these things can be distributed and/or even verified for "it works!" Due to this, it may of took a century for development, planning, making, testing, getting approved and mass distributing.
Four daughter cells from one single parent cell. Each daughter cell is haploid, because it has half the number of chromosomes as the original parent cell. Big brain science
