Polymerization reactions can only occur with unsaturated monomers due to the need for double bond breaking.

The statement is false. Polymerization can happen with both unsaturated and saturated monomers, but the mechanisms differ. Unsaturated monomers like ethylene break a C=C double bond so that new single bonds form, which is the basis for addition polymerization; saturated monomers can polymerize through condensation or ring‑opening reactions that do not require double‑bond breaking. For example, polyethylene is made from the unsaturated monomer ethylene, while polyester fibers come from saturated diols and diacids that condense to form long chains. Thus, polymerization is not limited to unsaturated monomers.