Final answer:
The foramen ovale, present in fetuses, develops into the fossa ovalis in adults.
Step-by-step explanation:
The foramen ovale, present in fetuses, develops into the fossa ovalis in adults. The foramen ovale is an opening in the interatrial septum that allows blood to flow from the right atrium to the left atrium during fetal development. After birth, the foramen ovale closes and leaves behind a small depression called the fossa ovalis.