You should give a picture of the fable!
Recycling!! And also planting more trees.
Hope this helps!
The mass of an element listed in the Periodic Table is the weighted average of all its naturally occurring isotopes.
Naturally occurring carbon is about
99 % carbon-12 (12.000 u) + 1 % carbon-13 (13.003 u).
That extra carbon-13 makes the <em>average atomic mass</em> greater than 12.000 u.
