In humans, the process of meiosis and the fertilization of the egg and the sperm ensures that the same offspring will never be created twice. Explain the three events during meiosis/fertilization that make this possible.

During synapsis, homologous chromosomes exchange genetic material between one another. This exchange is called crossing over. The process of independent assortment occurs during metaphase I where chromosomes from both parents align on the equator in an independent way therefore some from each parent on one side, and the opposite on the other. This means the gamete formed have a mixture of chromosomes from the parent's parents.

During fertilization, new genes from both parents combine in offspring that are different from those of the parents. Considering that in an individual there are thousands of genes that exist in two or more allelic forms, the number of possible gene combinations runs into millions. No wonder that no two children of a couple are identical except for identical twins who are products of the same egg and sperm.