Diffusion creep is, among other things, dependent on the diffusivity of the ions involved. If all other parameters are equal and if the grain boundary diffusivity is given by Dgb=110exp(40KJ/RT) and the bulk diffusion coefficient is given by Dlatt=321exp(50kJ/RT) Determine whether grain boundary (Coble Creep) or lattice diffusion (Nabarro-Herring Creep) will dominate at 709K. To record your final answer, enter 1 for Coble Creep or 2 for Nabarro-Herring Creep