Our mouths and tongues have taste buds, which are receptors for the five basic flavors: sweet, salty, sour, bitter, and umami, or what is more commonly referred to as savory.
They evolved to recognise only a few basic tastes in order to quickly identify toxins, which in nature are often quite bitter or acidly sour.
它们进化到能够识别出几种基本的味道，以便快速辨别毒素，而毒素在自然界中通常是很苦或很酸的。
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The basic operating requirements of sour water stripping tower are presented through analyzing the properties of solutions containing volatile weak electrolytes, such as ammonia and hydrogen sulfide.