What will be the effect on embryonic development if the placenta does not form after implantation? Explain.

Hint: The placenta is a very complex biological organ. It helps in the flow of blood from the mother to the body and back again. The mother's blood and the baby's blood are filtered through the placenta, but they never mix.

Complete answer:Development of placenta: The development of the placenta begins during implantation of the blastocyst. The 32-64 cell blastocysts contain two distinct differentiated embryonic cell types: the outer trophoblast cells and the inner cell mass. The trophoblast cells from the placenta.
The inner cell mass forms the foetus and foetal membranes.
-Implantation: It occurs on the 6th day, as the zona pellucida layer disintegrates from where the blastocyst “hatches” which allow implantation to take place. The trophoblast cells interact with the endometrial decidual epithelial which further enables the invasion into the maternal uterine cells.
-Functions of the placenta: The mother's blood and the baby's blood are filtered through the placenta, but they never actually mix. The placenta has an important role in hormone production as well. It also protects the fetus from harmful bacteria and infections.
-If it is not formed after implantation problems will occur: It can affect the developing baby's growth. Without proper oxygen and nutrients, the baby cannot grow and develop normally in the womb.
This increases the chances of complications during pregnancy and delivery.

Note: The placenta named on the basis of this organ’s gross anatomical appearance.
The placenta is a materno-fetal organ that begins developing at implantation of the blastocyst and is delivered with the fetus at birth. During that 9 month period, it provides nutrition, gas exchange, waste removal, a source of hematopoietic stem cells, endocrine and immune support for the developing fetus.