3. Haploid reproductive cells.

A haploid reproductive cell, either egg or sperm. Possessing a single set of chromosomes. Human gametes (eggs and sperm) are haploid cells because they only have a signle set of chromosomes. All other cells in the human body are diploid, meaning they possess two sets of chromosomes. A cell whose nucleus unites with that of a cell of the opposite sex to form a new organism. A reproductive cell contains only a single (haploid) set of chromosomes. Animal egg and sperm cells, the nuclei in grains of pollen, and egg cells in plant ovules are all reproductive cells. Also called gamete, sex cell