Ou are performing rescue breathing on a victim who was pulled unconscious from a swimming pool. after blowing slowly into your cpr mask until the victim's chest rises, you should: remove your mouth from mask, but cover the breathing part with your hand keep your mouth on the exhalation port while the victim exhales remove your mouth from the mask and allow the victim to exhale give a second rescue breath

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.