True or False. If false, correct the statement to be true. a. Hardness is a measure of the material's resistance to plastic deformation. b. Generally, hardness and yield stress are inversely related. c. Crystals deform by the generation and motion of large numbers of vacancies. d. Motion of a perfect dislocation creates a stacking fault behind on its slip plane. e. Edge dislocations can cross slip. f. The director pattern of a S=+1 disclination is unique. g. The Burgers circuit around a disclination line indicates the sign and strength of the defects enclosed by the circuit. h. The strain energy per unit length of both dislocation and disclination line defects scales as 1/r from the core of the defect. i. Tilt grain boundaries are comprised of an array of screw dislocations. j. There are two types of interphase grain boundary interfaces: semicoherent and incoherent