What clear liquid surrounds the fetus and serves to nourish and protect it?

Amniotic fluid is the clear liquid that surrounds the fetus during pregnancy. Its primary role is to provide a protective environment, cushioning the developing fetus from physical trauma and allowing for easier movement, which is essential for musculoskeletal development. Additionally, amniotic fluid plays a critical role in maintaining a consistent temperature and providing a medium for the fetus to practice breathing movements, which are important for lung development.

While the placenta is crucial for nutrient and gas exchange between the mother and fetus, it does not provide the same protective liquid environment as amniotic fluid. Uterine fluid is present in the uterus but is not specifically the fluid that surrounds the fetus. The chorion is one of the layers that develop around the embryo, but it is not the liquid that nourishes and protects the fetus directly. Therefore, amniotic fluid is the most appropriate choice given its specific role in the fetus's development during gestation.