This property is maintained at a wide range of frequencies in an insect protein containing many dityrosine and trityrosine crosslinks. Both a “series” and a “parallel” component with this property are described in Hill’s three element model. Worm-like chains such as DNA inherently have an entropic form of this property, while electrostatic interactions within PEVK regions cause a common example of this property's enthalpic form. This property is conferred by the I-band of the giant protein (*) titin (“TAI-tin”). Deficiencies in alpha-1 antitrypsin lead to breakdown of tissue with this property (10[1])in the lungs, (-5[1])which may cause COPD. Fibrils of collagen, fibronectin and a protein named for this property are a primary component of the extracellular matrix. For 10 points, name this property (10[1])of proteins that return to their original length after being (10[1])stretched. (10[1]) (10[2]0[1])■END■