Profit is producer surplus, minus fixed costs. In other words, its price minus variable costs. Profit, however, is price minus total cost. Since fixed cost is never negative, profit will always be less.
The atom is about 10-10 meters (or 10-8 centimeters) in size. This means a row of 108 (or 100,000,000) atoms would stretch a centimeter, about the size of your fingernail. Atoms of different elements are different sizes, but 10-10 m can be thought of as a rough value for any atom.
An atom is the smallest unit of matter.(well, there are smaller(quarks, leptons) but for the sake of simplicity, atoms are among the smallest) A molecule is something like H2O(water) and is made up of atoms. A cell is made up of atoms and molecules.