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Which of the following changes does not occur when a fetus is delivered
and begins to breathe on its own for the first time?
1. the rate of blood flow through
pulmonary circulation decreases
2. the foramen ovale closes
3. the ductus arteriosus closes
4. the resistance to blood flow
through the lung decreases

Sana , 6 Years ago
Grade 12
anser 1 Answers
Apurva Sharma

Last Activity: 6 Years ago

The answer is 1.
Because, at the time of birth the bypass of foramen ovale and ductus arteriosus cease to act with the start of breathing, and foramen ovale becomes fossa ovalis, ductus arteriosus becomes ligamentum arteriosum. 
Also increased oxygen in the lungs causes dectease in blood flow resistance to lungs.
 
Thus option 1 is the answer.
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