Before baby a was born, she was not sending much blood to her lungs. instead, the blood passed through the septal defect into the left atrium, which sent it to the left ventricle and to her body. but why didn't the baby die if no blood was going through her lungs?
(a) she was so small that the small amount of blood that did go through her lungs was enough
(b) she was getting her oxygen from placenta, not from breathing
(c) before the last trimester, babies use anaerobic respiration, so she did not need oxygen
(d) she sent her blood out into her mother's body and through her mothers lungs instead

The right answer is B.

The purpose of breathing is to do homeostasis, which means, to take CO2 out and get oxygen to our blood.

Babies live into the wound surrounded by liquid, so they don't need to breathe with their lungs.

All the things they needed to survive are taken from the mother thought the placenta.

The correct answer is option (B) "She was getting her oxygen from placenta, not from breathing".

Explanation:

In order to get the oxygen we need to live is necessary that the blood gets through our lungs. If an unborn baby has a problem that does not allow her to get blood to her lungs, she is still able to survive because she could get her oxygen from placenta, not from breathing. Placenta has a respiratory function that allows the baby for fetal oxygen supply and fetal carbon dioxide removal.