The chickens of Chernobyl and Belarus have frizzed feathers since the radiation leak and are not producing eggs. Feathers are composed of keratin, a protein and you already know that eggs are composed of protein and fat. You do further testing and find only the nucleic acids are affected in the chickens.
The World Health Organization sends you to Belarus (a Country affected by the accident) to try to determine which of the radioactive elements released moved over that Country. Which is the radioactive element and why?