Answer;
-Blood because a lower H+ concentration means a higher pH.
Step-by-step explanation;
-pH is a measure of the hydorgen ion concentration of a solution. Solutions with a high concentration of hydrogen ions have a low pH and solutions with a low concentrations of H+ ions have a high pH.
-Most organism’s need to keep their pH within a very small range (around 7). pH can be regulated by buffers, compounds that can bind to an H+ ion when the H+ concentration increases and can release H+ ions when the H+ concentration decreases.