This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

The roots of Presbyterianism lie in the European Reformation of the 16th century; the example of John Calvin's Geneva being particularly influential. Most Reformed churches which trace their history back to Scotland are either presbyterian or congregationalist in government. In the twentieth century, some Presbyterians played an important role in the ecumenical movement, including the World Council of Churches. Many Presbyterian denominations have found ways of working together with other Reformed denominations and Christians of other traditions, especially in the World Communion of Reformed Churches. Some Presbyterian churches have entered into unions with other churches, such as Congregationalists, Lutherans, Anglicans, and Methodists. Presbyterians in the United States came largely from Scotch-Irish immigrants communities, and also from New England Yankee communities that had originally been Congregational but changed because of an agreed-upon "Plan of Union of 1801" for frontier areas.
Where do most presbyterian churches trace their history back to?