During mammalian embryo development, large amounts of oestrogen and progesterone are produced in the

Large amounts of oestrogen and progesterone are produced in the placenta during mammalian embryo development. The placenta is a specialized organ that develops in the uterus during pregnancy and is responsible for exchanging nutrients, gases, and waste products between the mother and the developing fetus. The placenta is formed from both maternal and fetal tissues and contains a network of blood vessels that allow for the exchange of substances. The placenta is also responsible for producing hormones, including oestrogen and progesterone, which help to maintain the pregnancy and support the growth and development of the fetus.