Whenever possible, the most efficient way to perform rescue breathing is mouth to mouth or also known as CPR. By this the rescuer is giving air to someone who needed it or someone who is in need of air.
C. they grow quickly due to the chemicals
My best guess would be D. many studies have linked cardiorespiratory exercise to the lowering of blood pressure. (Many studies have also linked going vegan to the lowering of blood pressure, too :)
They Protect Us From Risk
