I want to know the answer to the following question:
Which group do marsupials and placentals belong to?
All the background I'm provided with is that "In an influential 1988 paper, Timothy Rowe defined Mammalia phylogenetically as the crown group mammals, the clade consisting of the most recent common ancestor of living monotremes (echidnas and platypuses) and therian mammals (marsupials and placentals) and all descendants of that ancestor.". Is that enough to answer the question?