The following substances pass into the blood of the foetus from the mother's blood via the placenta except

The placenta is an organ that connects the mother's blood supply to the developing foetus, allowing for the exchange of nutrients, oxygen, and waste products. Carbon dioxide and glucose are two examples of substances that pass from the mother's blood into the foetus's blood through the placenta. However, viruses do not pass from the mother's blood to the foetus's blood through the placenta. Similarly, antibodies, which are produced by the mother's immune system, can cross the placenta and provide passive immunity to the foetus against certain infections, so they also pass from the mother's blood to the foetus's blood through the placenta.