The chemical element einsteinium-253 naturally loses its mass over time. A sample of an einsteinium-253 had an initial mass of 540 g when we measured it. The relationship the elapsed time T in months and the mass m(t) in grams left in the sample is modeled by the following function m(t)=540•(1/8)^t/2.05 complete the following sentence about the rate of change in the mass of the sample