Final answer:
Babies more than 35 weeks gestational age requiring Positive Pressure Ventilation should initially be given 21% oxygen, which is the amount found in room air.
Step-by-step explanation:
If a baby who is more than 35 weeks gestational age requires Positive Pressure Ventilation (PPV), the initial concentration of oxygen to be given is 21%. Babies at this gestational age often have sufficiently developed lungs to start with room air for resuscitation. If the baby does not respond well, oxygen concentration can be increased gradually under controlled and monitored conditions. It is critical to avoid high oxygen concentrations initially to reduce the risk of oxygen toxicity and oxidative stress, which can lead to complications such as retinopathy of prematurity or bronchopulmonary dysplasia.