Is just a chemical reaction that compels animals to breed.

不过是让动繁衍后代的化学反应罢了。

For bioluminescence, creatures require two unique chemicals.

为了发光，需要两种独特的化学质。

Now, how did you discover these chemicals?

你们是怎样发现化学品？

Cigarette smoke contains 69 chemicals that are known to cause cancer.

香烟含有69种致癌化学质。

It also generates reactive chemicals that attack the microbes from within.

它还能产活性化学质，这种化学质能从内部攻击微。

They analyzed bacteria, fungi, parasites and chemicals.

他们分析了细、真、寄虫和化学质。

Fertilizer is a chemical that helps plants grow.

化肥是一种帮助长的化学质。

There are two important chemicals found in all our brains - dopamine and acetylcholine.

多巴胺和乙酰胆碱。

Never use harsh chemicals that can discolor the boot.

千万不要使用强效化学质，以免靴子褪色。

Industries pollute rivers by dumping poisonous chemicals into them.

工业企业向河流倾倒的有毒化学质，污染了水源。

A train derailment earlier this month spilled toxic chemicals.

本月早些时候，一列火车脱轨，泄漏了有毒化学质。

What's the plants' motivation for producing such chemicals?

那么制造这样一种化学质是何缘由呢?

The airbags contain a chemical that could make them explode.

气囊内含有能够造成爆炸的化学质。

They contain a harmful chemical that caused my liver to fail.

药里含有一种能导致肝功能衰竭的有害化学质。

It was easy to get the chemicals, but he needed the bodies.

添加剂很容易得到，但是没有测试者。

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质。

Asthma attacks can be triggered by pollen, dust, harsh chemicals or scents.

花粉、灰尘、刺激性化学质或气味可引发哮喘。

The light emitted by your devices releases wakeful chemicals in your brain.

设备的屏幕光会在大脑中释放出让人清醒的化学质。

If we mix these two chemicals together, they will form an acid.

如果我们把这两种化学混合在一起，他们会形成酸。

In the fields, farmers use too many chemicals which destroy the soil.

农民在田地里用了太多化学品，破坏了土壤。