Zygote

Zygote

When a female (human) egg is fertilized, it is no longer classified simply as an egg but is now considered a zygote. For two weeks, the zygote goes through an amazing amount of development that occurs in the form of cell division. The cells of the zygote divide very rapidly, thus doubling during each division (we all start as just a single-celled organism, but this changes very quickly).”