Which of the following is not one of the body's chemical buffering systems? a) hydrochloride b) protein c) bicarbonate d) phosphate

A

Explanation:

Buffers are molecules that  resist fluctuations in pH by donating or accepting electrons  with the introduction of more  acids or bases to a solution.

Their  general function in all living organisms  is to maintain relatively constant  blood plasma pH  for effective biochemical reactions.

In living cells  examples  are;

Carbonic acid bicarbonate;  buffer system to neutralise elevated hydrogen ion from high blood carbon dioxide

Protein buffer system;  mopping of excess hydrogen ions by haemoglobin

Phosphate buffer system ;, for neutralisation of excess  hydrogen ions   by releases of hydrogen phosphate  ions  

Therefore A is odd.