The above posts list the Biblical reasons why we believe in the Eucharist — do you believe that Christ is present in the Eucharist?
As for the reasons why I do not believe these things, you know perfectly well why biblical Christianity does not believe in transubstantiation, the so-called eucharist, Christ being physically present in the eucharist or the "sacrifice of the mass for the sins of the living and the dead". The reasons have been explained to you and to other Roman Catholics, numerous times on FR but you willfully refuse to accept the scriptural evidence found in John chapter 6 in context, and elsewhere in Scripture as to why such an interpretation is totally spurious. Therefore, for me to restate the reasons again is pointless because you have already rejected them.
For anyone reading this post who have an open heart and mind to learn the truth regarding the false-doctrine of "transubstantiation", the following article entitled: "FIFTY-FIVE THESES AGAINST TRANSUBSTANTIATION" found here:
http://www.spiritone.com/~wing/nontrans.htm
does an excellent job of presenting the biblical and historical reasons for refuting the unscriptural doctrine of transubstantiation.