The earthly elements used in this sacrament are bread and fruit of the vine. Fruit of the vine can either be wine or grape juice, although Lutherans traditionally use wine. The Lord's Supper also conveys His grace upon those who partake of it, meeting the last requirement for a Lutheran sacrament. Real presence states that the body and blood of Jesus Christ are really present with the bread and wine. Transubstantiation says that the bread and wine are actually changed into the body and blood of Jesus Christ.
Representation merely says that the body and blood are only represented by the bread and wine.
Lutherans believe that the teaching of real presence is the correct one. To show why they believe this, we will once again look at the words of Luke in chapter 22 verses 19 and 20. He explicitly states that the bread is the body of Christ, not that it represents the body or changes into the body of Christ. Lutherans believe that by the partaking of Communion, they are offered the blessings of forgiveness of sins, life, and salvation. By the partaking of Communion, one does not receive these blessings, because they have already been given to us.