Which was not a result of the 1898 discovery of the four blood types and advances made during the two World Wars?

Identifying blood types made transfusions safer by helping doctors match compatible donors and recipients. Advances during the World Wars also led to ways to preserve blood and separate it into components for different medical uses. Blood types were not made universally compatible; people still need appropriately matched blood, so “all blood types were made universally compatible” was not a result.

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