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

碘是一种富含、类和鲜的天然矿物质。

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化学物质。

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

这些化学物质、这些天然物质的性质是么？

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物质至关重要。

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成了一种独特的天然物质——mortiamides。

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

原油是复杂碳氢化物的混物——存在于石油、煤炭和天然气中的物质。

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物的物质中，不管你信不信，那是一种冰。

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化物的元素开始，这是一种对人类无害的天然物质， 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% 天然的有机物质。这对你有好处。这叫做烟草。- 谢谢医生。