What leads to the formation of a zygote?

The formation of a zygote occurs through the union of the male sperm and the female ovum. When a sperm cell successfully penetrates an ovum during the process of fertilization, their genetic materials combine, resulting in a single-celled entity known as a zygote. This zygote contains a complete set of chromosomes, half from the male parent (sperm) and half from the female parent (ovum), establishing the genetic blueprint for its future development.

Other options describe different stages or processes related to reproduction. Incubation refers to the conditions required for the fertilized egg to develop but does not lead to zygote formation. The development of the embryo follows after the zygote forms and begins dividing, while the release of multiple eggs from the ovary is part of the female reproductive cycle but does not directly relate to zygote formation. Only the union of sperm and ovum directly results in a zygote.