Answer:
(2) the placenta allows nutrients to diffuse from the mother to the embryo.
Step-by-step explanation:
The placenta is a shared organ between the mother and the embryo. It diffuses the necessary nutrients from the mother to the future baby and the residues from this one to the mother, so that she can expel them. The placenta separates the mothers and the embryo blood, but it allows the diffusion of said nutrients and wastes through especial parts of the placenta with thin walls.