What one type of strain results when rock responds to stress by permanently deforming without breaking?

The type of strain that results when rock responds to stress by permanently deforming without breaking is known as ductile strain. This occurs when rocks are subjected to high temperatures and pressures, allowing them to bend or flow rather than fracture. Ductile deformation is typically observed in deeper crustal levels where conditions promote such behavior. This contrasts with brittle strain, where rocks break or fracture under stress.