Question

Foramen ovale/fossa ovalis is present in
A. Partition between inner and middle ear
B. Interauricular septum
C. Interventricular septum
D. Aortic and pulmonary arches

Answer 1

Hint: Foramen ovale is the depression found in the right atrium, which is present in the interatrial septum, while the fossa ovalis is the remnant found after the developmental stage of the fetus.

Complete answer:
During the development of the fetus, the right atrium has a depression-like structure which is present between the interatrial septum.
The blood from the right atrium will flow to the left atrium through the foramen ovale. And this opening of the foramen ovale is covered by the septum primum.
Oxygen to the fetus is obtained from the placenta. So even though the mixing of blood happens also does not affect the fetus.
But when the development of the fetus is completed, the lungs start breathing, it starts to take oxygen which inflates the lungs and it applies the pressure in the thoracic region, which fuses the septum primum with the opening called foramen ovale.
Once the fusion occurs, this ovale forms the remnant in the septal wall and forms the fossa ovalis.
Almost in all people, this foramen ovale closes, once the lungs start pulmonary circulation.
By the age of two years, 75% of the kids have completed this closing the foramen ovale.
In some people, it does not close and remains patent.
In most people it is asymptomatic, but in some it requires surgery.

So. the Correct option: B. Interauricular septum.

Note:
Aneurysm is the condition, which occurs in the adults, which foramen ovale does not close properly, and aneurysm happens, when arteries get enlarged in a localized area, due to the weakening of the arterial wall.