Here "brothers" refers to fellow believers, both male and female. AT: "Fellow believers, because of the great mercy that God has given you I very much want you" (See: [[rc://en/ta/man/translate/figs-explicit]])
Here Paul uses the word "bodies" to refer to the whole person. Paul is comparing a believer in Christ who completely obeys God to the animals that the Jews killed and then offered to God. AT: "to offer yourselves completely to God while you are alive as if you were a dead sacrifice on a temple altar" (See: [[rc://en/ta/man/translate/figs-synecdoche]] and [[rc://en/ta/man/translate/figs-metaphor]])
Possible meanings are 1) "a sacrifice that you give to God alone and that pleases him" or 2) "acceptable to God because it is morally pure" (See: [[rc://en/ta/man/translate/figs-doublet]])