The structure marked A begins to close by what time frame and due to what cause?
The structure marked is ductus aeriosus which begins to close 10-15 hours after bih due to withdrawal of prostaglandins and exhibits functional closure by 7 days and anatomical closure by 4 weeks after bih.
Begins to close at 10-15 hours after bih, due to withdrawal of prostaglandins
Begins to close at 10-15 hours after bih, due to expression of prostaglandins
Begins to close 4 weeks after bih, due to fall in oxygen concentration
Begins to close 4 weeks after bih, due to rise in oxygen tension
Pharyngeal arch and its derivatives, pharyngeal arch aeries