LOOOOOOONG STORY. Haha, basically he sacrificed it to bring his brother back... but it'd make more sense if you read the manga (or watched fma:b, either is good!) (:
Definitely! It's a really excellent show! (There are two separate anime though. Fullmetal Alchemist: Brotherhood is the one that follows the manga. I personally prefer it over the first Fullmetal anime)
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or three times