There is a famous quote from the Talmud: "Whoever saves one soul is like saving the whole world".
The origin of this quote in the Babylonian Talmud is a Mishna (Sanhedrin 4:5), but the translation is inaccurate, because the Mishna only speaks about a Jewish soul (Sanhedrin 37a). The Kehati Mishna has the same version as the Talmud. However, in the Talmud Yerushalmi I found the quote without specifying a Jewish soul.
My question is which one is the accurate? How can we find out which is the original tradition, or if it was two different tradition at the beginning? What does it mean, that the Mishna is different in the Bavli and the Yerushalmi? I heard that if there is a contradiction in halacha we follow the opinion of the Bavli, what about this situation? Is there a Mishna edition today besides the Yerushalmi that contains the more inclusive version of this mishna?
I found the answer for my last question in the similar topic: The Mishna of Mechon Mamre, Mishna Sanhedrin 4:5 based on Rambam manuscript contains the same version as the Yerushalmi.
My other questions still remains.