Which of the following defines a haploid cell?

A haploid cell is defined as a cell that contains a single set of chromosomes, which is half the number of chromosomes typically found in diploid cells. In sexually reproducing organisms, haploid cells are crucial because they are the gametes—sperms and eggs—that combine during fertilization.

In contrast, diploid cells contain paired chromosomes, one from each parent, which means they hold two sets of chromosomes. Options related to processes like fertilization or mitosis are not relevant to the definition of haploidy itself, but rather highlight different stages of cell division or reproductive events. Hence, understanding that a haploid cell has only one set of chromosomes provides clarity on its role in reproduction and genetic diversity.