Subject: the 3 types of Blood Buffers

Hello.  I am a high school student in Indiana. Recently, my chemistry 
teacher
asked if anyone knew the 3 types of Blood Buffers that allow the blood to 
keep
its pH balance at the same level. We were able to come up with 2 of them,
                                                                   -2
                                            H    PO    /HPO
                                              2       4         4


            And

                                        H   CO    /HCO

                                           2       3            3

But we failed to come up with the 3rd buffer. My teacher could not htink of 
it
either, so he said that if we could do some research and find the other 
buffer,
it would be worth bonus points.  (I could really use them)  I've racked my
brain, searched encyclopedias, and the net and I couldnt find it.  I was 
wondering if you could help me out. It would be greatly appreciated.

Thank you for your time,

Evan

Re: the 3 types of Blood Buffers