Answer: Hypothalamus
You can confidently predict that this aspect of kidney function would be controlled by hypothalamus
Step-by-step explanation:
Hypothalamus is the part of the brain found just below the thalamus. It plays an important role in homeostasis i.e maintaining balance of water and electrolyte in the body.
The amount of electrolyte such as hydrogen ions in the body is controlled by the hypothalamus, when it stimulate the kidney to excrete excess hydrogen ions through urine, or retain hydrogen ions from urine.
Thus, hypothalamus is the answer