any four from:
1 gas exchange / oxygen transfers to fetus / oxygen transfers from mother / carbon dioxide transfers to mother / carbon dioxide transfers from fetus ;
2 transfers of (dissolved) nutrients, from maternal / to fetal (circulation);
3 transfer of excretory products, from fetal / to maternal (circulation) ;
4 (transfer of nutrients / excretory products) by diffusion ;
5 (placenta) produces / secretes, (named) hormone ;
6 transfer of antibodies, from maternal / to fetal (circulation) OR passive immunity provided (to fetus) ;
7 (placenta) separates fetal and maternal blood supply ; ora
8 AVP ;