The cell cycle has been the subject of intense investigation ... are turned off just before meiotic divisions, and those of the zygote are not turned on until the midblastula stage.

That's because fraternal twins happen when you release more than one egg in a menstrual cycle ... zygote usually happens between three and seven days after fertilization, when it's at the two-cell ...

These two haploid cells produce a diploid zygote. Hormonal control of reproduction Hormones control puberty, the menstrual cycle, and sperm production and play a crucial role in in the control of ...

These two haploid cells produce a diploid zygote. Hormonal control of reproduction Hormones control puberty, the menstrual cycle, and sperm production and play a crucial role in in the control of ...