What are the products of simple decomposition?

Which statement is best described as a atom

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

The comparison of the number of atoms in a copper coin the size of a penny with the number of people on earth is made to illustrate which of the following? a. that atoms are indivisible b. that atoms are very small c. that atoms are very large d. that in a copper penny, there is one atom for every person on earth