Iodine is a mineral naturally rich in seaweed, fish, and seafood.

碘是一种富含海藻、鱼类和海鲜的天然矿质。

Exercise releases endorphins which are natural feel-good chemicals in the body.

运动可以释放内啡肽，这是一种让人感觉良好的天然质。

Now what are the properties of these chemicals, of these natural substances?

这些质、这些天然质的性质是什么？

Chemical recycling uses enzymes, natural chemicals which cause changes in other chemicals without being changed themselves.

回收用到酶，这是一种引起其他质的变却不会改变身的天然质。

But they also discovered that this weird-looking fungusis synthesizing unique natural substances, mortiamides.

但他们也发现，这种长相怪异的真菌合成了一种独特的天然质——mortiamides。

And this step is essential to release the natural substanceswithin the lichen cell.

这一步对于释放地衣细胞内的天然质至关重要。

Crude oil is a mix of complex hydrocarbons – substances found in oil, coal and gas.

原油是复杂碳氢合的混合——存在于石油、煤炭和天然气中的质。

It's found in something called gas hydrate and, believe it or not, that's a kind of ice.

它存在于一种叫做天然气水合的质中，不管你信不信，那是一种冰。

The mother-daughter team then mixes the bacteria with a natural algae-based substance, called a gel, and places it onto the paintings.

然后，母女团队将细菌与一种名为凝胶的天然藻类质混合，并将其放置在画作上。

This story starts with an element called Bromide, a natural substance that is harmless to humans and is formed in the water from salt.

这个故事从一种叫做溴的元素开始，这是一种对人类无害的天然质， 是由盐在水中形成的。

Don't eat potatoes and tomatoes. They'll kill you. Here, smoke this. It's 100% natural, organic substance. It's good for you. It's called tobacco. - thanks, doctor.

不要吃土豆和西红柿。它们会杀了你。来，抽这个。它是 100% 天然的有机质。这对你有好处。这叫做烟草。- 谢谢医生。

With a rating of ten on the Mohs hardness scale, which measures the relative hardness of minerals, diamonds are the hardest known naturally occurring substance.

钻石的莫氏硬度等级为 10 级（用于测量矿的相对硬度），是已知最硬的天然质。

The Search for Our Natural Energy-Burner Knowing the power of DNP to literally burn through our stored (fat) energy, scientists have for decades been striving to find its natural equivalent within our bodies.

寻找我们身的天然能量燃烧剂。了解DNP能够直接燃烧我们储存的（脂肪）能量的威力后，数十年来，科家一直在努力寻找我们体内与之相当的天然质。