Chemistry The radio-active element used in heart pacemakers is ___________? Options:A. UraniumB. DeuteriumC. PlutoniumD. RadiumView AnswerC. Plutonium Continue Reading Previous: __________ is one of the allotropic modifications of carbon.Next: Water Gas is a mixture of two gases Hydrogen & Carbon monoxide, while separating Hydrogen gas by liquification process which one is liquefied first__?