Answer: Meiosis; fertilization
In the human life cycle, diploid cells undergo a cell division process called meiosis. The resulting haploid cells later fuse during fertilization which regenerates diploid cells.
Explanation:
Diploid cells possess two basic sets of chromosomes known as homologous chromosomes. They undergo a two-step meiosis (Meiosis I and II) to yield four haploid cells with half the original chromosome number of the parent cell. These haploid cells are called sex cells or gametes.
The male and female gametes (sperm and egg) then fuses during fertilization to form zygote, a single cell with two sets of chromosomes (diploid number). Then, it undergoes mitosis to regenerates diploid cells with the same chromosome number as found in the zygote.
