What type of cell division reduces the chromosome number by half?

Meiosis is the type of cell division that reduces the chromosome number by half. This process is essential for sexual reproduction, as it produces gametes, such as sperm and eggs, which carry half the genetic information of an organism.

During meiosis, a single precursor cell undergoes two sequential divisions—meiosis I and meiosis II. These divisions result in the separation of homologous chromosomes and then sister chromatids, ultimately leading to four non-identical daughter cells with half the original chromosome number. This reduction is vital because when fertilization occurs, the fusion of two gametes restores the diploid chromosome number, maintaining the stability of the species' genetic makeup across generations.

While mitosis is involved in growth and repair by producing clones of the original cell with the same chromosome number, meiosis specifically plays a distinct role in sexual reproduction and genetic diversity. Cloning and asexual reproduction also do not involve the reduction of chromosome count but rather result in offspring that are genetically identical to the parent organism.