Chromosome number is preserved through the processes of mitosis and meiosis. Mitosis is a type of cell division that results in two daughter cells each having the same number of chromosomes as the parent cell. Meiosis, on the other hand, reduces the chromosome number by half, producing four gametes (sperm or eggs), each with half the chromosome number of the parent cell. This reduction is crucial for sexual reproduction, as it ensures that the offspring have the correct chromosome number.
