The spice cinnamon and the drugs cascara and quinine (all come) from bark, the protctive (out) layer of (stems and roots) of woody (plants). all come错在哪里啊?还有out和outer有什么区别?

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all come没错，out用法错误。out是介词，不能用来修饰名词layer,应该用outer（形容词）来修饰。