Arrange the following in order of size, from smallest to largest: polymer, monomer, carbon atom,
macromolecule.

We can arrange the following entities from sizes smallest to largest in:
1.                                 Carbon atom. Consider the carbon atom in the periodic table which evidently small in size. Like any other atom such as hydrogen and oxygen.
2.                                 Monomer. Is a singular molecule that can combine itself with elongated chains and other molecules. And thus form,
3.                                 Polymer. Polymers are made from a complex amalgamation of monomers.
4.                                 Macromolecule. And thus the macromolecules from the word macro are the biggest component. Which forms the lipid, proteins, RNA enzymes in the cell. 

C) electrons encircling a nucleus with neutrons and protons