Answer the following question given this paragraph: 

Placenta of a Placental Mammal (Human). The placenta allows the exchange of gases, nutrients, and other substances between the fetus and mother.


Q: What mammalian structure allows the exchange of gases, nutrients, and other substances between the fetus and mother?

 Choices:

- uterus

- mitochondria

- notochord

- placenta

A:
placenta
