A disc-like special tissue developed between the uterus wall (called urine wall) and the embryo (or foetus) is called placenta. The foetus is connected to the mother's body through the umbilical cord. It is through the placenta that all the requirements of the developing foetus like nutrition, respiration, and excretion etc. are met from the mother's body. In other words, the exchange of nutrients, oxygen and waste products b/w the embryo and the mother takes place through the placenta.