The thyroid gland gathers and concentrates iodine from the bloodstream. The radioactive isotope -131, with a half-life of 193 h, can consequently be used as a marker in determining how well the hyroid gland is functioning. An initial amount of 5.00 x 10 g is given to a patient. a. The patient is tested 2.00 h after the l-131 is taken. How much of the material is left in the patient's body? b. What percent of the original quantity is left after one year? How much time is required for the amount to fall to C. 1 of the original quantity? 100