http://www.anatomyzone.com. 3D anatomy tutorial providing a basic introduction to respiratory anatomy using the Zygote Body Browser (http://www.zygotebody.com). This is the second part of the tutorial and covers the bronchial tree and lungs.Join the Facebook page for updates: http://www.facebook.com/anatomyzone.his is the second part of the tutorial and covers the bronchial tree and lungs. Join the Facebook page for updates: http://www.facebook.com/anatomyzone.
The average atomic mass of carbon is 12.011. This is a weighted average based on three forms (isotopes) of carbon with different natural abundances. Carbon 12 has an atomic mass of 12.00 (carbon 12 is a special case because its mass is <i>defined</i> to be exactly 12 atomic mass units) and a natural abundance of 0.9893.
According to HowStuffWorks, an atomic mass unit is defined as the mass of a single proton or neutron. Hydrogen, the lightest element, has an average mass of 1.00794 amu. A carbon-12 atom is made up of six protons and six neutrons, hence 12 atomic mass units. The mass of the electron is considered negligible, therefore electrons are not counted in measuring an atom's atomic mass.