Final answer:
The fetal lungs are fully developed by week 32, allowing the fetus to start breathing on its own.
Step-by-step explanation:
By about week 32, the fetal lungs are most likely fully developed. This is important because it allows the fetus to start breathing on its own. Prior to this stage, the fetus receives oxygen from the mother through the placenta. However, after the lungs are fully developed, the fetus is capable of breathing independently.
Learn more about Fetal lung development