Los Alamos National Lab scientists are studying how microbes in the soil can slow down the spread of what long-lived radioisotope that is readily absorbed in the thyroid?

W) Strontium-90 [STRAWNCH-ee-um-90]

X) Iodine-131

Y) Cesium-137 [SEEZ-ee-um-one-thirty-seven]

Z) Iodine-129
Z) IODINE-129