1 The largest school district by enrollment with an election in 2016 is Wake County Public School System with 153,534 K-12 students.  The smallest North Carolina school district among the nation's largest with an election in 2016 is Duplin County Schools with 9,628 K-12 students.
Freon only remains a liquid while under pressure inside your refrigerator's cooling system. The chemical changes to a gas as soon as it contacts the air. This means, when you smell freon in and around your refrigerator, you're also inhaling varying amounts of freon gas. According to the Environmental Protection Agency, freon gas is denser than air and travels very slowly to the upper atmosphere.
So, lots of tiny air sacks (alveoli) have a greater surface area (absorptive surface for oxygen) than simple lungs without alveoli (amphibians have these simple lungs and have to supplement oxygen absorption by the lungs with oxygen absorbed through their wet skins) To demonstrate this we usually look at cubes: a 1cm cube has a surface are of 1x1x6=6, and a volume of 1x1x1=1 (suface are to volume ratio=6); increase to a cube of 2cm, results in a surface area of 2x2x6=24, and ...