In 1940 , it was discovered that uranium could be artificially changed to plutonium, a process called transmutation. what combination of decay processes would convert u-239 (92 protons) into pu-239 (94 protons)?

The combination of decay processes that would convert U-239 into PU- 239 is beta decay followed by another beta decay. Beta decay involves the emission of an electron [positron]. There are two types of beta decay; positive and negative beta decays and both occur simultaneously in order to move the atoms towards stability. 

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