Final answer:
The blender should be set to 21% for the initial resuscitation of newborns.
Step-by-step explanation:
For the initial resuscitation of newborns greater than or equal to 35 weeks gestation, the blender should be set to 21%. This is because newborns have a higher concentration of oxygen in their blood compared to adults, so a lower percentage of oxygen is needed for resuscitation. Setting the blender to 21% ensures that the newborn receives an appropriate amount of oxygen without risking oxygen toxicity.