All these elements are natural radioactive elements.
Francium exist in uranium and thorium ores.
Natural polonium exist in uranium or thorium ores.
Natural polonium exist in uranium and thorium ores.
Natural polonium exist in uranium and thorium ores.
Francium exist in uranium and thorium ores but it is not exploitable.
Francium exists in uranium and thorium ores.
Polonium exist in traces in uranium and thorium ores.
Francium exist in infinitesimal concentrations in uranium and thorium ores.
Francium exist in infinitesimal traces in thorium and uranium ores.
Natural francium exist in uranium and thorium ores.Artificial francium is obtained in particle accelerators.
Polonium isotopes are decay products of thorium or uranium.
Natural francium exist in uranium and thorium ores.