What structural feature differentiates step growth polymers from chain growth polymers?

Step growth polymers are always linear, while chain growth polymers form networks.

Step growth polymers have higher molecular weights than chain growth polymers.

Step growth polymers use cyclic monomers, while chain growth polymers use linear monomers.

Step growth polymers often form networks due to multifunctional monomers, while chain growth polymers typically form linear chains.