The comparison of the number of atoms in a copper coin the size of a penny with the number of people on earth is used to
illustrate which of the following:
that atoms are indivisible
that atoms are very small
that atoms are very large
thatina copper penny, there is one atom for every person on earth

Probably it was ment to illustrate how significant and indivisible, being very small, atoms are and how each of them under normal conditions of presure and temperature find their own place eventually

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.