Iodine is eliminated from the body through biological processes with an effective half-life of about 140 days. The radioactive half-life of iodine-131 is 8 days. Suppose some radioactive 131I nuclei are present in the body. Assuming that no new 131I nuclei are introduced into the body, how much time must pass until only half as much 131I is left in the body: less than 8 days, between 8 and 140 days, or more than 140 days? Explain your reasoning.