Background: For the most tissues and organisms, oxygen is necessary factor to maintain vital activities.

背景对大部分的组织器官而言，氧是维持生命活动的必需因素。

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Background: For the most tissues and organisms, oxygen is necessary factor to maintain vital activities.

背景对大部分的组织器官而言，氧是维持生命活动的必需因素。

youdao