It is mitosis, in which both diploid and haploid cells undergoes this process. If a diploid cell undergoes mitosis, it results in two identical diploid cells. $2n \rightarrow n$ If a haploid cell undergoes mitosis, the result is two identical haploid cells ($n \rightarrow n$). In meiosis however, a diploid cell participates that divides twice to produce four haploid cells