In humans the fetal heart has an opening between the right and left atria, called the foramen ovale.This opening normally closes at birth.Failure of the foramen ovale to close can result in so-called "blue babies" when it is associated with other heart defects.What might explain the babies' bluish appearance?
A) High blood pressure
B) Mixing of blood with different oxygen contents
C) Low metabolic rate
D) Few systemic blood vessels
E) Low blood pressure

Question

Quizplus · Accepted Answer

Mixing of blood with different oxygen contents can cause a bluish appearance, known as cyanosis. If the foramen ovale fails to close, it can allow oxygen-poor blood from the right atrium to mix with oxygen-rich blood from the left atrium, resulting in cyanosis.

In Humans the Fetal Heart Has an Opening Between the Right