Soil should also be tested for its pH level, a measure of the acid and alkaline balance.

VOA: special.2009.06.09

In addition, the kidney controls the composition of your body of many important ions, sodium bicarbonate which is important in pH balance, potassium.

此外肾脏还能控制,体内很多重要离子的浓度,例如碳酸氢钠,它对于酸碱平衡十分重要,还有钾离子

耶鲁公开课 - 生物医学工程探索课程节选