'all polymers are macromolecules but all macromolecules are not necessarily polymers.' comment upon the statement.
The polymers are also called as macromolecules because of their big size. A polymer always consists of thousands of repeating monomers units. However a macromolecule is a giant molecule which may or may not contain monomer units. For example chlorophyll is a macromolecule but it is not a polymer as it does not contains monomer whereas polythene is a polymer as well as macromolecules as it contains large number of repeating monomers. Thus all the polymers are macromolecules but reverse is not true.