Help me on question 5 pls

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

How are isotopes of the same element alike?

How can you write e method for the experiment of separating sand from water by filtration process? 1-materials 2-steps 3-conclusion also the same for the separating process of water and salt by filtration or distillation. quick because i need to finish my hw