Each of the following claims was written in an article: 1. Particles smaller than 2.5 micrometers in diameter are easily inhaled deep into the lungs where they can accumulate, react, be cleared or absorbed. 2. According to the American Academy of Pediatrics (AAP), children and infants are among the most susceptible to many air pollutants. 3. Children have increased exposure to air pollution because of higher minute ventilation and higher levels of physical activity. 4. The average adult breathes 3,000 gallons of air per day. If you had no knowledge of the subject which claim should be the MOST credible?