Acertain protein, similar to silk, is very flexible but strong and is resistant to stretching. these properties are most associated with what
structure.

The flexibility and mobility of proteins are based on the number of domains that they are comprised of. These domains give give rise to their secondary, tertiary and finally their quaternary structures. The ability for these proteins to be strong and be flexible depend on how these domains interact with each other in terms of van der Waal's forces and also which type of domains are interacting.