Understand the difference between atom, molecule, salt (or ionic compound), and
compound

Whether something is a molecule or not depends on the type of bond that is formed when its atoms join together. ... Something like table salt (NaCl) is a compound because it is made from more than one kind of element (sodium and chlorine), but it is not a molecule because the bond that holds NaCl together is an ionic bond

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.