These are tobacco plants , the only natural source of nicotine.

这些是烟叶，提炼尼古丁的惟一自然资源。

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This special collagen supplement is a 100% natural source of absorbable collagen protein.

我们独特的产品来源于100%可被吸收利用的天然胶原蛋白。

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In the hopes that tigers will flourish (and not kill livestock) when they have a natural source of food.

我们希望老虎能够大量繁殖起来，并且当它们有自然食物资源时不会杀害家畜。

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This restriction enzyme was found in a natural source, it was found in a micro-organism called E.coli.

这个限制性内切酶源于自然界,是从名为大肠杆菌的微生物中发现的

耶鲁公开课 - 生物医学工程探索课程节选

Some fish, such as salmon and mackerel, are a good natural source of omega-3s.

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Beer naturally contains a shot of B vitamins. (Not coincidentally, vegans get excited about brewer's yeast.) This entrepreneur isn't the first to see nutrition as a selling point for booze: During World War II Anheuser-Busch advertised Budweiser as a natural source of B vitamins.

FORBES: Magazine Article

Beer naturally contains a shot of B vitamins. (Not coincidentally, vegans get excited about brewer's yeast.) This entrepreneur isn't the first to see nutrition as a selling point for booze: During World War II Anheuser-Busch (nyse: BUD - news - people ) advertised Budweiser as a natural source of B vitamins.

FORBES: To Your Health?