What is the process by which two haploid cells (1n) combine to form a diploid cell (2n) ?

In human haploid gametes, there are 23 chromosomes. One way to write this is " 1n = 23." As you learned in the previous activity, two haploid cells can combine, through the process of fertilization, to form a diploid zygote ... In other words, germ cells go through meiosis to produce gametes.