Answer:
Atom, cell, dust particle, ant, ping pong ball
Explanation:
Firstly, atoms make up all matter, including each of the items on that list. The only things smaller than atoms are the parts of the atom itself, protons, neutrons and electrons. Because none of those are on that list, atoms have to be the smallest. Next smallest is the cell. Cells are made up of atoms, but they also in part make up dust. You can see a dust particle with the naked eye, but in order to see a cell you must use a microscope. Thus, cells are smaller than dust particles. Next is an ant. Obviously, an ant is bigger than a speck of dust, and is made up of cells and atoms. Lastly all you have is the ping pong ball, which is much larger than the rest of the items. Hope this helps!