The blood electrolytes—sodium, potassium, chloride, and bicarbonate—help regulate nerve and muscle function and maintain acid-base balance and water balance. ... Thus, the kidneys help maintain a balance between daily consumption and excretion of electrolytes and water.
The most likely answer is B because a trough is a long hollow vessel for holding liquids.
If you are asking what D.N.A stands for, it's deoxyribo nucleuc acid<span>.</span>