What's the key features of a catholic church? what does the catholic church teach about mass sacrifice ?

It talks about it is the realy body and blood of jesus christ

So. In the old testement, mass sacrifice was considered the only way for your sins to be basically forgiven, butafter God gave us his son, we no longer need to sacrifice with things such as mass slaughter. But what the Catholic's failed to see BEFORE the protestant reformation, was that the old testement no longer applies to our lives now, but God has given us his son to save us. The key features of the Catholic Church BEFORE the reformation of protestant (christians) was that the only way for sins to be forgiven was with a connection to a priest or some form of more royalty in relation to the majority of the population. You also had to pay these people to let God forgive your sins. (I dont know if you've ever read the bible, but this is completely unorthodox.) Those are some key features of what the Catholic chruch before Luther. Some may still stick to these beliefs, but we, humanity, has come pretty far in understanding the writtings of the past, and especially the bible.

This link explains it