Answer:
Meiosis.
Step-by-step explanation:
Meiosis is the division of the nucleus of a eukaryotic cell with a decrease in the number of chromosomes by half. It occurs mostly in the creation of gametes (sperm and ova). With a decrease in the number of chromosomes as a result of meiosis, a transition from the diploid phase to the haploid phase occurs in the life cycle. The restoration of ploidy (the transition from the haploid phase to the diploid) occurs as a result of the sexual process.