Final answer:
The tissue does not return to its previous length after being stressed once it reaches the plastic region on the stress-strain curve, where any deformation becomes permanent.
Step-by-step explanation:
In a typical stress-strain curve, such as for mammalian tendon, the tissue will no longer return to its previous length after being stressed when it has reached the plastic region. Before the plastic region, the material behaves elastically, where it can return to its original shape and size once the load is removed.
However, in the plastic region, any deformation becomes permanent, and the material does not recover post-stress. This plastic deformation continues until the material reaches the fracture point, also known as the failure region, where the material breaks.