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 and occurs in the formation of gametes, such as sperm and eggs. During meiosis, a single diploid cell undergoes two rounds of division, ultimately producing four haploid cells, each containing half the number of chromosomes as the original cell. This reduction ensures that when gametes unite during fertilization, the resulting zygote maintains the correct diploid chromosome number characteristic of the species.

Mitosis, in contrast, is responsible for growth and repair in multicellular organisms and results in two genetically identical daughter cells, maintaining the same chromosome number as the parent cell. Binary fission is a form of asexual reproduction typically seen in prokaryotes like bacteria, where the cell divides into two identical cells, again maintaining the chromosome number. Regeneration refers to the process by which organisms can regrow certain parts of their body, which does not involve a reduction in chromosome number and relies on mitosis rather than the specialized process of meiosis.