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Blood. But I am still confused to determine which one is better.

blood

blood!

That's an interesting stat and I am still questioning which is better or which one makes more sense. Both of them are related to what parents are doing for their children.

You could say the U.S. does both. For example, no matter what country you are born in, if at least one of your parents is a U.S. citizen then you are eligible to be a citizen.