A former Russian service officer died in November 2006 after being diagnosed with acute radiation syndrome. During the investigation into his death, authorities were able to trace his activities, in part, because his body had excreted trace amounts of which of the following radioactive isotopes, which he had recently ingested?

W) Polonium-210 with a half-life of 138 days

X) Bismuth-213 with a half-life of 45 minutes

Y) Technetium-99 with a half-life of 6 hours

Z) Uranium-238 with half-life of 4.5 billion years
W) POLONIUM-210 WITH A HALF-LIFE OF 138 DAYS