a resting person requires 14.5 L of O2 per hour to maintain metabolic activities. Such a person breathes in 0.50 L of air at approximately 20 degrees C with each breath. The inhaled air is 20.9%O2 while the exhaled air is 16.3% O2. (a) how many breaths per minute does a resting person need to take to provide the necessary oxygen? (b) How many O2 molecules does a resting person inhale per breath?