In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.
Q: Leo:  You know , you guys can hassle your skinny friend Eric , but when it comes down to a fundamental moral core he 's the only one of you that 's got _ one _ . So congratulations , you 've ruined Christmas .
A: 
core