You are presented with the quiz "What may become unbalanced if the rate of breathing is too fast or too slow?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "blood pH may become unbalanced if the rate of breathing is too fast or too slow" and "for instance, the normal pH of human blood is maintained at 7.4". 

So, what's the best answer to the question?


 

  normal human blood         