The potential energy in molecules is stored in...

Energy, potential energy, is stored in the covalent bonds holding atoms together in the form of molecules. This is often called chemical energy. Except at absolute zero (the coldest temperature it is possible to reach), all molecules move.

Chemical energy

Explanation:

Energy, potential energy, is stored in covalent bonds holding atoms together in the form of molecules

the answer is:  

line graphs show patterns in data with variables that change over time; whereas, circle graphs show data as parts out of a whole (such as out of 100%).