Читать книгу Infants and Children in Context - Tara L. Kuther - Страница 140
Prenatal Development
ОглавлениеConception, the union of ovum and sperm, marks the beginning of prenatal development. Over 266 days (or 38 weeks), the human progresses from fertilization to birth. During this transformation, the zygote progresses through several periods of development, finally emerging from the womb as a neonate.