1. The foetus relies upon its mother as it develops.
- nutrients (food and water).
3. The placenta is responsible for providing oxygen and nutrients. (in the blood stream you have glucose, amino acids and fats that travel through to the wall of the uterus, then cross into the child's blood.
4. The placenta (has a large surface area) and grows into the wall of the uterus and is joined to the foetus by the umbilical cord.
- oxygen and nutrients diffuse across the placenta from the mother to the fetus
- waste substances, such as carbon dioxide, diffuse across the placenta from the fetus to the mother.