No, Martin Luther did not believe in transubstantiation. He rejected the Catholic doctrine that the bread and wine in the Eucharist physically transform into the body and blood of Christ. Instead, he believed in the concept of consubstantiation, where the body and blood of Christ coexist with the bread and wine.
Mexicans
Martin Luther believed in consubstantiation, also known as sacramental union, because he interpreted the Bible to teach that in the Eucharist, the bread and wine coexist with the body and blood of Christ. Luther rejected the Roman Catholic doctrine of transubstantiation, which teaches that the bread and wine are transformed into the literal body and blood of Christ.
Catholic, I don't think any others do.
Catholics are especially reverent toward the altar because it is where the process of transubstantiation takes place. Transubstantiation is the process in which the gifts of bread and wine are transformed into the body and blood of Christ though the Holy Spirit. Protestants do not believe in transubstantiation. Instead, Protestants believe that the bread and wine are symbols for Christ's body and blood.
I believe as well that another point which needs to be stressed here regards the issue of transubstantiation vs. consubstantiation. Lutherans as I recall do not believe in transubstantiation or the concept that at communion the "Lord's supper" literaly becomes the body and blood of Jesus as we observe and particiate in that act of worship. As I recall, Luther belived in consubstantion....not that the wine and bread literally became Jesus' body within us, but that at that observance there was at least a "presence" of the Holy Spirit there.
Members of the Church of Jesus Christ of Latter-days Saints (Mormons), do not believe in transubstantiation. They believe in the sacredness and importance of the Lord’s Sacrament, and take it weekly, using bread and water to represent the flesh and blood of Jesus Christ. But they do not believe the substances transform, and remain only as symbols of the Sacrifice of Jesus Christ.
Martin Luther believed that the body and blood of Christ really was present in the bread and wine of the sacrament.
Yes he did
Baptism and Eucharist
No
As you are not listing any of the possible "practices" in your question, I'm just going to take a stab in the dark; for instance, infant baptism was never a source of contention. Initially indulgences were not a source of contention (Luther was only objecting to the people's misunderstanding of indulgences), but later he rejected the entire system. One user said that the sacrament of communion was often an answer that they were looking for when this question is asked on a test, but Martin Luther most definitely did not believe in transubstantiation, he believed in consubstantiation. 1_ the sacrament of communion
As you are not listing any of the possible "practices" in your question, I'm just going to take a stab in the dark; for instance, infant baptism was never a source of contention. Initially indulgences were not a source of contention (Luther was only objecting to the people's misunderstanding of indulgences), but later he rejected the entire system. One user said that the sacrament of communion was often an answer that they were looking for when this question is asked on a test, but Martin Luther most definitely did not believe in transubstantiation, he believed in consubstantiation. 1_ the sacrament of communion